#include<iostream>
#include<sstream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<string>
#include<vector>
#include<cmath>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<numeric>
#include<functional>
#include<complex>

using namespace std;
#define BET(a,b,c) ((a)<=(b)&&(b)<(c))
#define FOR(i,n) for(int i=0,i##_end=(int(n));i<i##_end;i++)
#define SZ(x) (int)(x.size())
#define ALL(x) (x).begin(),(x).end()
#define MP make_pair
#define FOR_EACH(it,v) for(__typeof(v.begin()) it=v.begin(),it_end=v.end() ; it != it_end ; it++)
typedef vector<int> VI;
typedef vector<VI> VVI;

int main()
{
    int N, V;
    cin>>N>>V;
    VI C(N);
    vector<long long> S(N);
    FOR(i,N) cin>>C[i];
    S[0] = C[0];
    for(int i=1;i<N;i++) S[i] = S[i-1] + C[i];
    long long ans = S[N-1];
    V -= N;
    if(V > 0){
        int maxUnitIndex = 0;
        FOR(i,N) if(S[i] * (maxUnitIndex + 1) > S[maxUnitIndex] * (i+1)){
            maxUnitIndex = i;
        }
        int upper = N * N * N;
        if(upper < V){
            long long need = (V - upper) / maxUnitIndex;
            ans += need * S[maxUnitIndex];
            V   -= need * (maxUnitIndex+1);
        }
        vector<long long> dp(V + 1, 1LL<<60);
        dp[0] = 0;
        FOR(i,N) {
            FOR(j,V+1){
                dp[j] = min(dp[j], dp[j-(i+1)] + S[i]);
            }
        }
        ans += dp[V];
    }
    cout<<ans<<endl;
    return 0;
}