#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#ifdef LOCAL
#include <algo/debug.h>
#else
#define debug(...) void(0)
#endif

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N; cin >> N;
    string S; cin >> S;
    map<char, int> MP;
    for(int i = 0; i < N; i++) MP[S[i]]++;
    for(auto&&[a, b]: MP) {
        if(b >= 2) {
            cout << "Yes" << endl;
            return 0;
        }
    }
    cout << "No" << endl;
}