/* -*- coding: utf-8 -*-
 *
 * 2322.cc:  No.2322 MMA文字列 - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

/* typedef */

/* global variables */

/* subroutines */

/* main */

int main() {
  char s[8];
  scanf("%s", s);

  if (s[0] == s[1] && s[0] != s[2]) puts("Yes");
  else puts("No");
  
  return 0;
}