#include <bits/stdc++.h>
using namespace std;

#define ll long long

void solve() {
    int n;
    string s;
    cin >> n >> s;

    unordered_map<char, int> mp;
    for(char ele : s) {
        if(mp[ele] == 1) {
            cout << "Yes" << endl;
            return;
        }
        else mp[ele]++;
    }
    cout << "No" << endl;
       
}
 
int main(){
    ios::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);
    // int t;
    // cin >> t;
    // while(t--){
    //     solve();
    // }
    solve();
    return 0;
}