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

int main()
{
    int N;
    cin >> N;
    vector<int> A(N);

    for (int i = 0; i < N; i++)
    {
        cin >> A[i];
    }
    int Min = 2 * 1e9;
    for (int i = 0; i < N; i++)
    {
        Min = min(Min, A[i]);
    }
    if (Min >= 2)
    {
        cout << "No";
        return 0;
    }

    cout << "Yes";
}