#include <bits/stdc++.h>
#define syosu(x) fixed<<setprecision(x)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<string> vs;
typedef vector<P> vp;
typedef vector<vp> vvp;
typedef vector<pll> vpll;
typedef pair<int,P> pip;
typedef vector<pip> vip;
const int inf=1<<30;
const ll INF=1ll<<60;
const double pi=acos(-1);
const double eps=1e-8;
const ll mod=1e9+7;
const int dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};

ll n,m;
vl a;

int main(){
	cin>>n>>m;
	a=vl(n);
	for(int i=0;i<n;i++){
		cin>>a[i];
		if(i) a[i]+=a[i-1];
	}
	m-=n;
	if(m<=0){
		cout<<a[n-1]<<endl;
		return 0;
	}
	ll M=min(10005ll,m+1);
	vl dp(M,INF);
	dp[0]=0;
	for(int i=0;i<n;i++){
		vl DP(M,INF);
		for(int j=0;j<M;j++) DP[j]=min(dp[j],(j>=i?DP[j-i-1]+a[i]:INF));
		dp=DP;
	}
	ll res=INF;
	for(int i=0;i<M;i++){
		ll N=m-i;
		for(int j=1;j<=n;j++) if(N%j==0) res=min(res,dp[i]+N/j*a[j-1]);
	}
	cout<<res+a[n-1]<<endl;
}