#include <bits/stdc++.h>
#define For(i, a, b) for(int (i)=(int)(a); (i)<(int)(b); ++(i))
#define rFor(i, a, b) for(int (i)=(int)(a)-1; (i)>=(int)(b); --(i))
#define rep(i, n) For((i), 0, (n))
#define rrep(i, n) rFor((i), (n), 0)
#define fi first
#define se second
using namespace std;
typedef long long lint;
typedef unsigned long long ulint;
typedef pair<int, int> pii;
typedef pair<lint, lint> pll;
template<class T> bool chmax(T &a, const T &b){if(a<b){a=b; return true;} return false;}
template<class T> bool chmin(T &a, const T &b){if(a>b){a=b; return true;} return false;}
template<class T> T div_floor(T a, T b){
    if(b < 0) a *= -1, b *= -1;
    return a>=0 ? a/b : (a+1)/b-1;
}
template<class T> T div_ceil(T a, T b){
    if(b < 0) a *= -1, b *= -1;
    return a>0 ? (a-1)/b+1 : a/b;
}

constexpr lint mod = 1e9+7;
constexpr lint INF = mod * mod;
constexpr int MAX = 1000010;

int main(){
    int n; lint V;
    scanf("%d%lld", &n, &V);
    lint C[n], sum = 0;
    rep(i, n){
        scanf("%lld", &C[i]);
        sum += C[i];
    }
    V -= n;
    if(V <= 0){
        printf("%lld\n", sum);
        return 0;
    }

    partial_sum(C, C+n, C);
    lint dp[MAX];
    fill(dp, dp+MAX, INF);
    dp[0] = 0;
    rep(i, n)rep(j, MAX)if(dp[j] < INF){
        if(j+(i+1) < MAX) chmin(dp[j+(i+1)], dp[j] + C[i]);
    }

    int m = 0;
    For(i, 1, n){
        if(C[m]*(i+1) > C[i]*(m+1)) m = i;
    }
    lint ans = INF;
    rep(i, MAX)if(i <= V){
        chmin(ans, sum + dp[i] + C[m]*div_ceil(V-i, (lint)m+1));
    }
    printf("%lld\n", ans);
}