#include<iostream>
#include<string>
#include<algorithm>
#include<cctype>
#include<set>
#include<bitset>
#include<math.h>
#include<map>
#include<queue>
using namespace std;

int main(){
    string a, b, c, d;
    cin >> a;
    b = a[0], c = a[1], d = a[2];
    if (a.size()==3){
        if ((b == c && b != d)) cout << "Yes" << endl;
        else cout << "No" << endl;
    }
    else cout << "No" << endl;
}