#include <iostream>
#include <algorithm>
#include <string>
#include <cstring>
#include <vector>
#include <map>
#include <queue>
#include <cmath>
#include<set>
#include<stack>
#include<deque>
#include<cassert>
#include <bits/stdc++.h>
#define rep(i,n) for (int i=0; i<(int)(n); i++)
using namespace std;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
typedef long long ll;
typedef pair<int,int> P;
using Graph = vector<vector<int>>;
//#define INF 10000000
class UnionFind{
    public:
    vector<int> par;

    UnionFind(int n) : par(n){
        for(int i=0; i<n; i++) par[i] = -1;
    }

    int root(int x){
        if(par[x] == -1) return x;
        int next = par[x];
        return root(next);
    }

    void unite(int x, int y){
        int px = root(x);
        int py = root(y);
        if(px == py) return;
        par[px] = py;
    }

    bool same(int x, int y){
        int px = root(x);
        int py = root(y);
        if(px == py) return true;
        else return false; 
    }
};



bool isPrime(int x){
    bool prime = true;
    for(int i=2; i<x; i++){
        if(x%i == 0){
            prime = false;
            break;
        }
    }
    if(!prime) return false;
    return true;
}


//------------------------------------------------------------------------//

ll n,m;
vector<ll> a;

bool isOk(ll key){
    ll t = key*m;
    ll sum = 0;
    bool res = true;
    for(int i=0; i<n; i++){
        sum += a[i];
        if(sum < t){
            res = false;
            break;
        }
        t += key*m;
    }
    return res;
}

int main(){
    cin >> n >> m;
    a.resize(n);
    rep(i,n) cin >> a[i];

    ll right = 1000000010;
    ll left = 0;
    while(right - left > 1){
        ll mid = (right + left)/2;
        if(isOk(mid)) left = mid;
        else right = mid;
    }
    cout << left << endl;
}