#include <bits/stdc++.h>

using namespace std;
using LL = long long;

int main(){

    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    LL n , p;
    cin >> n >> p;

    vector<LL> a(n + 1);
    for(int i = 1 ; i <= n ; i ++ )
        cin >> a[i];

    __int128 sum = 0;
    for(int i = 1 ; i <= n ; i ++ ){
        if(p <= sum + a[i] + (__int128)i * (a[i] - 1)){
            cout << i - 1 << "\n";
            return 0;
        }
        sum += a[i];
    }

    cout << n << "\n";

    return 0;
}