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

#define IOS ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define endl "\n"
#define int long long
#define F first
#define S second
#define all(x) (x).begin(), (x).end()

const int inf = 1e18;


// int dx[4]={-1,0,1,0};
// int dy[4]={0,1,0,-1};

// int dx[8]={0,-1,-1,-1,0,1,1,1};
// int dy[8]={1,1,0,-1,-1,-1,0,1};

const int N = 200200;
const int mod = 1e9+7;
using ii = pair<int,int>;


void solver(){
    int n;cin>>n;

    int flg = 0;

    for(int i=0;i<n;i++)
    {
        int x;cin>>x;
        if(x==0 || x==1)
        {
            flg = 1;
        }
    }

    if(flg)
    {
        cout<<"Yes"<<endl;
    }
    else
    {
        cout<<"No"<<endl;
    }


}


signed main()
{
    IOS
    //int _t;cin>>_t;while(_t--)
    solver();
    return 0;
}

#undef int