#pragma GCC optimize("O3")
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#pragma GCC optimize("Ofast")
#pragma GCC optimize("inline")
#pragma GCC optimize("-fgcse")
#pragma GCC optimize("-fgcse-lm")
#pragma GCC optimize("-fipa-sra")
#pragma GCC optimize("-ftree-pre")
#pragma GCC optimize("-ftree-vrp")
#pragma GCC optimize("-fpeephole2")
#pragma GCC optimize("-ffast-math")
#pragma GCC optimize("-fsched-spec")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("-falign-jumps")
#pragma GCC optimize("-falign-loops")	
#pragma GCC optimize("-falign-labels")
#pragma GCC optimize("-fdevirtualize")
#pragma GCC optimize("-fcaller-saves")
#pragma GCC optimize("-fcrossjumping") 
#pragma GCC optimize("-fthread-jumps")
#pragma GCC optimize("-funroll-loops")
#pragma GCC optimize("-freorder-blocks")
#pragma GCC optimize("-fschedule-insns")
#pragma GCC optimize("inline-functions")
#pragma GCC optimize("-ftree-tail-merge")
#pragma GCC optimize("-fschedule-insns2")
#pragma GCC optimize("-fstrict-aliasing")
#pragma GCC optimize("-falign-functions")
#pragma GCC optimize("-fcse-follow-jumps")
#pragma GCC optimize("-fsched-interblock")
#pragma GCC optimize("-fpartial-inlining")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("-freorder-functions")
#pragma GCC optimize("-findirect-inlining")
#pragma GCC optimize("-fhoist-adjacent-loads")
#pragma GCC optimize("-frerun-cse-after-loop")
#pragma GCC optimize("inline-small-functions")
#pragma GCC optimize("-finline-small-functions")
#pragma GCC optimize("-ftree-switch-conversion")
#pragma GCC optimize("-foptimize-sibling-calls")
#pragma GCC optimize("-fexpensive-optimizations")
#pragma GCC optimize("inline-functions-called-once")
#pragma GCC optimize("-fdelete-null-pointer-checks")
#pragma GCC optimize("Ofast")
//#pragma GCC target("avx,avx2,fma") 
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native") 
//#pragma GCC optimization ("unroll-loops")

#include <bits/stdc++.h>
 
using namespace std;

int main(void)
{
	cin.tie(0);
	ios::sync_with_stdio(false);

    int n,k;
    long long int t;
    vector <long long int> A;

    cin >> n >> k;

    for(int i=0;i<n;i++)
    {
        cin >> t;
        A.push_back(t);
    }    

    long long int lo = 1e16;
    long long int hi = 1e16;

    for(int i=0;i<n;i++)
    {
        lo = min(lo,A[i]);
    }

    long long int res = lo;

    while(lo<=hi)
    {
        long long int mid = (lo + hi)/2;
        long long int add = 0;
        long long int sum = 0;

        for(int i=0;i<n;i++)
        {
            if(A[i] + add >= mid) continue;
            long long int diff = mid - A[i] - add;
            long long int step = diff/(i+1);
            if(diff%(i+1)!=0) step += 1;
            sum += step;
            add += (step*(i+1));
        }

        if(sum > k)
        {
            hi = mid - 1;
        }
        else
        {
            lo = mid + 1;
            res = max(res,mid);
        }

        //cout << mid << ' ' << sum << '\n';
    }

    cout << res << '\n';

	return 0;
}