UnityでAndroid用にビルドできない

こんにちは。UnityでAndroid用にビルドしたら以下のようなエラーが出てしまいました。
同じクラスファイルがあるためだというのは分かるのですが、どのファイルを消せば良いのか分からない状態です。
どのファイルを消すべきなのか教えて頂きたいです。
拙い説明ではありますが、ご教授お願いします。
文字数の都合上下部はカットしております。
CommandInvokationFailure: Unable to convert classes into dex format. See the Console for details.
/Library/Java/JavaVirtualMachines/jdk1.8.0_101.jdk/Contents/Home/bin/java -Xmx2048M -Dcom.android.sdkmanager.toolsdir="/Users/NakaoRyo/Library/Android/sdk/tools" -Dfile.encoding=UTF8 -jar "/Applications/Unity/PlaybackEngines/AndroidPlayer/Tools/sdktools.jar" -

stderr[
Uncaught translation error: java.lang.IllegalArgumentException: already added: Lcom/unity3d/ads/android/BuildConfig;
Uncaught translation error: java.lang.IllegalArgumentException: already added: Lcom/unity3d/ads/android/IUnityAdsListener;
Uncaught translation error: java.lang.IllegalArgumentException: already added: Lcom/unity3d/ads/android/UnityAds;
Uncaught translation error: java.lang.IllegalArgumentException: already added: Lcom/unity3d/ads/android/UnityAds$1;
Uncaught translation error: java.lang.IllegalArgumentException: already added: Lcom/unity3d/ads/android/UnityAds$2;
Uncaught translation error: java.lang.IllegalArgumentException: already added: Lcom/unity3d/ads/android/UnityAds$3;
Uncaught translation error: java.lang.IllegalArgumentException: already added: Lcom/unity3d/ads/android/UnityAdsDeviceLog;
Uncaught translation error: java.lang.IllegalArgumentException: already added: Lcom/unity3d/ads/android/UnityAdsDeviceLog$1;
Uncaught translation error: java.lang.IllegalArgumentException: already added: Lcom/unity3d/ads/android/UnityAdsDeviceLog$UnityAdsLogLevel;

UNEXPECTED TOP-LEVEL EXCEPTION:
java.lang.RuntimeException: Translation has been interrupted
at com.android.dx.command.dexer.Main.processAllFiles(Main.java:613)
at com.android.dx.command.dexer.Main.runMonoDex(Main.java:311)
at com.android.dx.command.dexer.Main.run(Main.java:277)
at com.android.dx.command.dexer.Main.main(Main.java:245)
at com.android.dx.command.Main.main(Main.java:106)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at SDKMain.main(SDKMain.java:129)
Caused by: java.lang.InterruptedException: Too many errors
at com.android.dx.command.dexer.Main.processAllFiles(Main.java:605)
... 9 more
]
stdout[
processing archive /Users/NakaoRyo/Desktop/UnityProject/3Donidori/Temp/StagingArea/android-libraries/nend-unity-plugin/libs/./classes.jar...
processing net/nend/unity/plugin/BannerDelegate.class...
processing net/nend/unity/plugin/BannerDelegate$BannerAdListener.class...
processing net/nend/unity/plugin/BannerDelegate$BannerLayoutUpdater.class...
processing net/nend/unity/plugin/BannerDelegate$BannerParams.class...
processing net/nend/unity/plugin/BaseDelegate.class...
processing net/nend/unity/plugin/BaseDelegate$LayoutUpdater.class...
processing net/nend/unity/plugin/BaseDelegate$NendGravity.class...
processing net/nend/unity/plugin/BuildConfig.class...
processing net/nend/unity/plugin/IconDelegate.class...
processing net/nend/unity/plugin/IconDelegate$IconAdListener.class...
processing net/nend/unity/plugin/IconDelegate$IconGroupParams.class...
processing net/nend/unity/plugin/IconDelegate$IconHolder.class...
processing net/nend/unity/plugin/IconDelegate$IconLayoutUpdater.class...
processing net/nend/unity/plugin/IconDelegate$IconParams.class...
processing net/nend/unity/plugin/IconDelegate$NendOrientation.class...
processing net/nend/unity/plugin/InterstitialDelegate.class...
processing net/nend/unity/plugin/InterstitialDelegate$1.class...
processing net/nend/unity/plugin/InterstitialDelegate$UiSystemVisibilityCompat.class...
processing net/nend/unity/plugin/InterstitialDelegate$UiSystemVisibilityCompatBeforeKitkat.class...
processing net/nend/unity/plugin/InterstitialDelegate$UiSystemVisibilityCompatKitkat.class...
processing net/nend/unity/plugin/InterstitialDelegate$UiSystemVisibilityCompatKitkat$1.class...
processing net/nend/unity/plugin/NendAdIconViewWrapper.class...
processing net/nend/unity/plugin/NendPlugin.class...
processing net/nend/unity/plugin/NendPlugin$1.class...
processing net/nend/unity/plugin/NendPlugin$10.class...
processing net/nend/unity/plugin/NendPlugin$11.class...
processing net/nend/unity/plugin/NendPlugin$12.class...
processing net/nend/unity/plugin/NendPlugin$13.class...
processing net/nend/unity/plugin/NendPlugin$14.class...
processing net/nend/unity/plugin/NendPlugin$15.class...
processing net/nend/unity/plugin/NendPlugin$16.class...
processing net/nend/unity/plugin/NendPlugin$17.class...
processing net/nend/unity/plugin/NendPlugin$2.class...
processing net/nend/unity/plugin/NendPlugin$3.class...
processing net/nend/unity/plugin/NendPlugin$4.class...
processing net/nend/unity/plugin/NendPlugin$5.class...
processing net/nend/unity/plugin/NendPlugin$6.class...
processing net/nend/unity/plugin/NendPlugin$7.class...
processing net/nend/unity/plugin/NendPlugin$8.class...
processing net/nend/unity/plugin/NendPlugin$9.class...
processing net/nend/unity/plugin/NendUnityNativeAdClient.class...
processing net/nend/unity/plugin/NendUnityNativeAdClient$1.class...
processing net/nend/unity/plugin/NendUnityNativeAdClient$SimpleNativeAdListener.class...
processing net/nend/unity/plugin/NendUnityNativeAdListener.class...
processing archive /Users/NakaoRyo/Desktop/UnityProject/3Donidori/Temp/StagingArea/android-libraries/nend-unity-plugin/libs/./nendSDK-3.1.1.jar...
processing net/nend/android/A.class...
processing net/nend/android/A$1.class...
processing net/nend/android/A$a.class...
processing net/nend/android/B.class...
processing net/nend/android/B$1.class...
processing net/nend/android/C.class...
processing net/nend/android/C$1.class...
processing net/nend/android/C$2.class...
processing net/nend/android/C$a.class...
processing net/nend/android/D.class...
processing net/nend/android/D$1.class...
processing net/nend/android/E.class...
processing net/nend/android/F.class...
processing net/nend/android/G.class...
processing net/nend/android/H.class...
processing net/nend/android/I.class...
processing net/nend/android/J.class...
processing net/nend/android/J$1.class...
processing net/nend/android/J$2.class...
processing net/nend/android/J$2$1.class...