#include <iostream>
using namespace std;
int main()
{
    int n,m;
    cin >> n >> m;
    int time[n];
    for( int i = 0; i < n; ++i)
    {
        cin >> time[i];
    }
    int sum = 0;
    for(int i=n-1,j = 1; i >= 0; i--,j++)
    {
        sum = sum + time[i] * j;
    }
    if ( sum >= m )
        cout << "YES";
    else
        cout << "NO"; 
    return 0;     
}