配列にScannerで入力しようとするとエラーが出る

https://onlinejudge.u-aizu.ac.jp/courses/lesson/2/ITP1/4/ITP1_4_C
Java初心者です。
上記のサイトの問題を解いていて
for文の中にある配列a[]にScannerで入力する行でエラーが起こります

Java
import java.util.Scanner;
class Main {
    public static void main(String[] args){
       
        Scanner sc = new Scanner(System.in);
        //int w = sc.nextInt();
        //System.out.println("Hello World"); 
        int[] a;
        a = new int[3000];
        int[] b;
        b = new int[3000];
        int[] ans;
        ans = new int[3000];
        String[] op;
        op = new String[3000];

        for(int i=0;i<1000;i++){
            op[i] = sc.next();
            a[i] = sc.nextInt();
            b[i] = sc.nextInt();

            if(op[i].equals("+")){
                    ans[i] = a[i] + b[i];
              }
            else if(op[i].equals("-")){
                    ans[i] = a[i] - b[i];
            }
            else if(op[i].equals("*")){
                    ans[i] = a[i] * b[i];
            }
            else if(op[i].equals("/")){
                    ans[i] = a[i] / b[i]; 
            }
            else if(op[i].equals("?")){
                    break;
            }
        
        }
        int i = 0;
        while(true){
             if(op[i].equals("?")){break;}
            System.out.println(ans[i]); 
            i++;
        }
        return;
    }

}

エラー文 Exception in thread "main" java.util.InputMismatchException at java.base/java.util.Scanner.throwFor(Scanner.java:939) at java.base/java.util.Scanner.next(Scanner.java:1594) at java.base/java.util.Scanner.nextInt(Scanner.java:2258) at java.base/java.util.Scanner.nextInt(Scanner.java:2212) at Main.main(Main.java:20) Command exited with non-zero status 1 0.08user 0.00system 0:00.05elapsed 178%CPU (0avgtext+0avgdata 44212maxresident)k 0inputs+80outputs (0major+4128minor)pagefaults 0swaps