#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
//#include<cctype>
#include<climits>
#include<iostream>
#include<string>
#include<vector>
#include<map>
//#include<list>
#include<queue>
#include<deque>
#include<algorithm>
//#include<numeric>
#include<utility>
#include<complex>
//#include<memory>
#include<functional>
#include<cassert>
#include<set>
#include<stack>

const int dx[] = {1, 0, -1, 0};
const int dy[] = {0, 1, 0, -1};
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<int, int> pii;

const int MAXN = 111;
const ll INF = 1ll<<60;
ll C[MAXN], S[MAXN];
pair<ll, int> P[MAXN];

ll dp[MAXN][MAXN*MAXN];

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    ll V;
    cin >> N >> V;
    for (int i = 0; i < N; i++) {
        cin >> C[i];
    }
    S[0] = C[0];
    P[0] = make_pair(S[0], 1);
    for (int i = 1; i < N; i++) {
        S[i] = S[i-1] + C[i];
        P[i] = make_pair(S[i], i+1);
    }
    ll ans = S[N-1];
    V -= N;
    if (V <= 0) {
        cout << ans << endl;
        return 0;
    }
    sort(P, P+N, [](const pair<ll, int>& lhs, const pair<ll, int>& rhs) -> bool {return lhs.first*rhs.second < rhs.first*lhs.second;});
    // V の残りが N^2 になるまでは引いていっても良い
    ll ok = V-N*N;
    if (ok > 0) {
        ll num = ok/P[0].second;
        if (ok%P[0].second) num++;
        ans += P[0].first*num;
        V -= P[0].second*num;
    }
    assert(V <= N*N);
    // 後は dp
    for (int i = 0; i < N; i++) for (int j = 0; j <= N*N; j++) dp[i][j] = INF;
    dp[0][0] = 0;
    for (int i = 0; i < N; i++) {
        if (i > 0) {
            for (int j = 0; j <= N*N; j++) {
                dp[i][j] = min(dp[i][j], dp[i-1][j]);
            }
        }
        for (int j = 0; j <= N*N; j++) {
            if (j-(i+1) >= 0) dp[i][j] = min(dp[i][j], dp[i][j-i-1]+S[i]);
        }
    }
    cout << ans + dp[N-1][V] << endl;
    return 0;
}