直接用的字符串遍历

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        int a = sc.nextInt();
        int sum = 0;
        for (int i = 0; i < s.length(); i++) {
            if(s.charAt(i) == '3'){
                sum ++;
            }
        }
        if(sum == a){
            System.out.println("YES");
            return;
        }
        System.out.println("NO");
    }
}