#include <bits/stdc++.h>
#include <atcoder/all>
using ll = long long;
#define MOD 1000000007
#define Mod 998244353
const int MAX = 1000000005;
const long long INF = 1000000000000000005LL;
using namespace std;
using namespace atcoder;



int main() {
    ios::sync_with_stdio(0);cin.tie();
    string S;
    cin >> S;
    set<char> se;
    for (int i = 0; i < 3; i++) se.insert(S[i]);
    cout << (se.size() == 2 and S[0] == S[1] ? "Yes" : "No") << endl;
}