#include <iostream>
#include <vector>
#define rep(i, l, n) for (int i = (l); i < (n); i++)
using namespace std;
using ll = long long;
template <class T>
using V = vector<T>;


bool func(V<ll>&a, ll n, ll m, ll k) {
	ll s = 0;
	ll t = m * k;
	bool res = true;
	rep(i, 0, n) {
		s += a[i];
		if (s < t) {
			res = false;
			break;
		}
		t += m * k;
	}
	return res;
}


int main(void) {
	ll n, m;	cin >> n >> m;
	V<ll> a(n);
	rep(i, 0, n) {
		cin >> a[i];
	}

	ll ok = 0;
	ll ng = 1000000001;
	while (ng - ok > 1) {
		ll k = (ok + ng) / 2;
		if (func(a, n, m, k)) {
			ok = k;
		}
		else {
			ng = k;
		}
	}

	cout << ok << '\n' << endl;
	return 0;
}