#include <vector>
#include <iostream>
#include <string>
#include <ostream>
#include <map>
#include <set>
#include <bitset>
#include <cmath>
#include <iomanip>
#include <algorithm>
#include <list>
#define rep(i, n) for (int i = 0; i < (n); i++)
using namespace std;

int main()
{
    int n;
    string s;
    cin >> n >> s;
    map<char, int> mp;
    rep(i, n)
    {
        if (mp[s[i]] == 1)
        {
            cout << "Yes" << endl;
            return 0;
        }
        mp[s[i]]++;
    }
    cout << "No" << endl;
}