Problem:
Score : 100 points

Problem Statement

You are given a 4-character string S consisting of uppercase English letters.
Determine if S consists of exactly two kinds of characters which both appear twice in S.

Constraints

The length of S is 4.

S consists of uppercase English letters.

Input

Input is given from Standard Input in the following format:

S

Output

If S consists of exactly two kinds of characters which both appear twice in S, print Yes; otherwise, print No.

Sample Input 1

ASSA

Sample Output 1

Yes

S consists of A and S which both appear twice in S.

Sample Input 2

STOP

Sample Output 2

No

Sample Input 3

FFEE

Sample Output 3

Yes

Sample Input 4

FREE

Sample Output 4

No

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;
public class Main{
  public static void main(String[]args){
      Scanner sc = new Scanner(System.in);

      String S =sc.nextLine();

      char c;
      char[] data  = new char[S.length()];
      int count  = 0;

      for(int i = 0;i<S.length();i++){
        c = S.charAt(i);
        data[i] = c;
      }
      for(int i =0;i<2;i++){
        for(int j = i+1;j<4;j++){
          if(data[i]==data[j]){
            count++;
          }
        }
      }
      if(count==2){
        System.out.println("Yes");
      }else{
        System.out.println("No");
      }


  }
}