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`.

Examples

Input

ASSA


Output

Yes


Input

STOP


Output

No


Input

FFEE


Output

Yes


Input

FREE


Output

No
#include <bits/stdc++.h>
using namespace std;
int main() {
  char s[4];
  for(int i=0;i<4;++i) cin >> s[i];
  sort(s,s+4);
  if(s[0]==s[1]&&s[2]==s[3]&&s[1]!=s[2]) cout << "Yes" << endl;
  else cout << "No" << endl;
}