#ifndef SHO_LOCAL
#include <bits/stdc++.h>
#define debug(...) ;
#else
#include "debug.h"
#endif
using namespace std;
using ll = long long;
int main() {
  iostream::sync_with_stdio(0), cin.tie(0);

  int n, k;
  cin >> n >> k;

  vector<ll> A(n);
  for (int i = 0; i < n; i++) {
    cin >> A[i];
  }
  ll sum = 0;

  ll low = *min_element(A.begin(), A.end());
  ll high = *max_element(A.begin(), A.end()) + k + 1;

  while (high - low > 1) {
    sum = 0;
    ll x = (high - low) / 2 + low;
    ll cnt = 0;
    for (ll i = 0; i < n; i++) {
      ll need = x - A[i] - sum;
      ll now = 0;
      if (need > 0) {
        now = (need + i) / (i + 1);
        cnt += now;
      }
      sum = sum + now * (i + 1);
    }
    if (cnt <= k) {
      low = x;
    } else {
      high = x;
    }
  }
  cout << low << '\n';

  return 0;
}