// Problem: No.2217 Suffix+ No.2217后缀+
// Contest: yukicoder
// URL: https://yukicoder.me/problems/no/2217
// Memory Limit: 512 MB
// Time Limit: 2000 ms

#include <bits/stdc++.h>

#define fastio ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
#define dbg(x) cout << #x << " = " << (x) << "\n";
#define popcount(x) __builtin_popcountll((x))
#define all(v) (v).begin(), (v).end()
#define pb emplace_back
#define x first
#define y second

using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;

const int inf = 0x3f3f3f3f;
const int mod = 1e9 + 7;

const int N = 1e5 + 7;
ll n, k;
ll a[N];

bool ok(ll mn, ll t) {
  ll pre = 0;
  for (int i = 1; i <= n; i++) {
    if (a[i] + pre < mn) {
      ll need = (mn - (a[i] + pre) + i - 1) / i;
      pre += need * i;
      t -= need;
      if (t < 0) return false;
    }
  }
  return true;
}

void solve() {
  cin >> n >> k;
  for (int i = 1; i <= n; i++) cin >> a[i];
  ll l = 0, r = 1e16;
  while (l < r) {
    ll mid = (l + r + 1) >> 1;
    if (ok(mid, k))
      l = mid;
    else
      r = mid - 1;
  }
  cout << l << "\n";
}

int main() {
  fastio;
  int t = 1;
  // cin >> t;
  while (t--) {
    solve();
  }
  return 0;
}