#include #include #include using namespace std; int main(){ string S; int N = S.size(); vector cnt(26, 0); for (int i = 0; i < N; i++){ cnt[S[i] - 'A']++; } bool ok = true; for (int i = 0; i < 26; i++){ if (cnt[i] > 1){ ok = false; } } if (ok){ cout << "YES" << endl; } else { cout << "NO" << endl; } }