#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=(r)-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[9]={1,0,-1,0,1,1,-1,-1,0};
const ll dx[9]={0,-1,0,1,1,-1,1,-1,0};
template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
int main(){
    ll n,v;cin >> n >>v;
    vl a(n);rep(i,n)cin >> a[i];
    ll ans=accumulate(all(a),0LL);
    if(n>=v)cout << ans <<endl,exit(0);
    v-=n;
    if(v>=10000000)return 0;
    vl it(n);it[0]=a[0];
    rep(i,n-1)it[i+1]=it[i]+a[i+1];
    vector<ll> dp(v+1,INF);dp[0]=0;
    rep(i,n){
        rep(j,v+1){
            if(j+1+i<=v)chmin(dp[j+i+1],dp[j]+it[i]);
        }
        //rep(j,v+1)cout << dp[j]+ans <<" ";cout << endl;
    }
    cout << dp[v]+ans <<endl;
    //rep(i,v+1)cout << dp[i]+ans <<" ";cout << endl;
}