#include <bits/stdc++.h>
using namespace std;
 
#define fi first
#define se second
#define pb push_back
using vi = vector <int>;
using ll = long long;
using vl = vector <ll>;
using pii = pair <int, int>;
const ll mod = 998244353;
//~ const ll mod = 1e9 + 7;
ll qpow(ll a, ll b, ll m = mod) { ll r = 1, t = a;
	for(; b; b /= 2) { if(b & 1) r = r * t % m; t = t * t % m; } return r; }

const int N = 2e5 + 11;
ll a[N];

bool check(int n, ll mi, int k) {
	ll add = 0;
	for(int i = 1; i <= n; i ++) {
		if(a[i] + add < mi) {
			ll t = (mi - a[i] - add + i - 1) / i;
			if(t > k) return 0;
			k -= t;
			add += ll(i) * t;
		}
	}
	return 1;
}

int main() {
	ios::sync_with_stdio(0);
	int n, k; cin >> n >> k;
	for(int i = 1; i <= n; i ++)
		cin >> a[i];
	
	ll l = 0, r = 1e16;
	while(l + 1 < r) {
		ll m = (l + r) / 2;
		if(check(n, m, k))
			l = m;
		else
			r = m;
	}
	cout << l << '\n';
}