#include<iostream>
#include<vector>
#include<algorithm>

using namespace std;
using ll = long long;


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

    ll n,v;
    cin>>n>>v;
    vector<ll> c(n);
    for(int i = 0;i<n;i++) cin>>c[i];
    ll sum = 0;
    for(int i = 0;i<n;i++) sum += c[i];
    v -= n;
    if(v<=0){
        cout<<sum<<endl;
        return 0;
    }

    vector<ll> a(n+1,0);
    for(int i = 0;i<n;i++) a[i+1] += a[i] + c[i];
    ll ans = 1e18;
    vector<ll> dp(n+1,1e18);
    dp[0] = 0;
    for(int i = 0;i<=n;i++){
        for(int j = 1;j<=n;j++){
            if(i+j>n) continue;
            dp[i+j] = min(dp[i+j],dp[i]+a[j]);
        }
    }
    for(int i = 0;i<n;i++){
        ll le = i + 1;
        ll can = (v-n+le-1) / le;
        ll nv = v - can * le;
        ll now = sum + a[i+1] * can;
        if(nv>=0) now += dp[nv];
        ans = min(ans,now);
    }
    cout<<ans<<endl;
}