#include <bits/stdc++.h>
#include <atcoder/all>
using mint = atcoder::static_modint<998244353>;
//using mint = atcoder::static_modint<1000000007>;
using namespace std;
using namespace atcoder;
using ld = long double;
using ll = long long;
#define mp(a,b) make_pair(a,b)
#define rep(i,s,n) for(int i=s; i<n; i++)
const vector<int> dx{1,0,-1,0},dy{0,1,0,-1};

int main(){
    int n;
    cin >> n;
    bool findone=false;
    rep(i,0,n){
        int a;
        cin >> a;
        if(a==1)findone=true;
    }
    if(findone)cout << "Yes";
    else cout <<"No";
}