#include <bits/stdc++.h> using namespace std; #define F first #define S second #define R cin>> #define ln cout<<'\n' #define ll long long #define in(a) insert(a) #define pb(a) push_back(a) #define pd(a) printf("%.12f\n",a) #define mem(a) memset(a,0,sizeof(a)) #define all(c) (c).begin(),(c).end() #define iter(c) __typeof((c).begin()) #define rrep(i,n) for(ll i=(ll)(n)-1;i>=0;i--) #define REP(i,m,n) for(ll i=(ll)(m);i<(ll)(n);i++) #define rep(i,n) REP(i,0,n) #define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++) ll check(ll n,ll m,ll x,ll y){return x>=0&&x<n&&y>=0&&y<m;}void pr(){ln;} template<class A,class...B>void pr(const A &a,const B&...b){cout<<a<<(sizeof...(b)?" ":"");pr(b...);} template<class A>void PR(A a,ll n){rep(i,n)cout<<(i?" ":"")<<a[i];ln;} const ll MAX=1e9+7,MAXL=1LL<<61,dx[8]={-1,0,1,0,-1,-1,1,1},dy[8]={0,1,0,-1,-1,1,1,-1}; typedef pair<ll,ll> P; void Main() { ll n; string s; cin >> n >> s; set<char> se; rep(i,n) { if(se.count(s[i])) { pr("Yes"); return; } se.in(s[i]); } pr("No"); } int main(){ios::sync_with_stdio(0);cin.tie(0);Main();return 0;}