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

using ll = long long;

int main(void) {
	int N, V;
	cin >> N >> V;
	vector<int> C(N);
	for(int i = 0; i < N; ++i) cin >> C[i];
	
	vector<ll> S(N, 0);
	S[0] = C[0];
	for(int i = 1; i < N; ++i) S[i] = S[i - 1] + C[i];
	
	V -= N;
	ll ans = S[N - 1];
	if(V <= 0) {
		cout << ans << endl;
		return 0;
	}
	
	const int M = 12000;
	vector<ll> dp(M + 1, 1e18);
	dp[0] = 0;
	for(int i = 0; i < N; ++i) for(int j = 0; j <= M; ++j) dp[j + i + 1] = min(dp[j + i + 1], dp[j] + S[i]);
	
	if(V > M) {
		int k = 0;
		for(int i = 1; i < N; ++i) if(S[k] * (i + 1) < S[i] * (k + 1)) k = i;
		
		ll t = (V - 10500) / (k + 1);
		ans += S[k] * t;
		V -= t * (k + 1);
	}
	
	ll mdp = 1e18;
	for(int i = 0; i < 1000; ++i) mdp = min(mdp, dp[V + i]);
	
	cout << ans + mdp << endl;
	return 0;
}