Euler’s criterion in java

According to Euler’s criterion a square root of n under modulo p exists if and only if a number num exists such that num%p is equal to n%p.

Program

import java.util.Scanner;

public class EulersCriterion {
   public static void main(String args[]) {
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter n value :");
     
      int n = sc.nextInt();
      System.out.println("Enter p value :");
      int p = sc.nextInt();
      n = n % p;
      int flag = 0;
     
     for (int num = 2; num < p; num++) {
         if ((num * num) % p == n) {
            flag = 1;
         }
      }
      if(flag==1) {
         System.out.println("root of a number under modulo p exists ");
      } else {
          System.out.println("root of a number under modulo p does not exists ");
      }
   }
}

Output

Enter n value :
2
Enter p value :
7
root of a number under modulo p exists