#include <bits/stdc++.h>

using namespace std;
int a[1000000];
int n, m;

int check(int k) {
  int res = 0;
  for (int i = 0; i < n; i++) {
    if (a[i] - k > 0)
      res += a[i] - k;
  }
  return res;
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);

  freopen("ptit126j.inp", "r", stdin);

  cin >> n >> m;
  for (int i = 0; i < n; i++)
    cin >> a[i];
  sort(a, a + n);

  // 10 15 17 20
  int l = 0, r = a[n - 1];
  int res = a[n - 1];
  while (l < r) {
    int mid = (l + r) / 2;

    if (check(mid) >= m) {
      // cout << mid << "\n";
      res = mid;
      l = mid + 1;
    } else {
      r = mid;
    }
  }
  cout << res << '\n';
}