#include<bits/stdc++.h>
using namespace std;
//#include<atcoder/all>
//using namespace atcoder;
using ll = long long;
using ull = unsigned long long;
#define rep(i,n) for(int i=0;i<(n);++i)

int main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int n;
	cin >> n;
	string s;
	cin >> s;
	map<char,int> count;
	for(int i=0;i<n;++i){
		count[s[i]]++;
	}
	bool ok = false;
	for(auto it=count.begin();it!=count.end();++it){
		if(it->second>=2)ok = true;
	}

	ok ? cout << "Yes" << endl : cout << "No" << endl;

}