// includes
#include <bits/stdc++.h>

// macros
#define ll long long int
#define pb emplace_back
#define mk make_pair
#define pq priority_queue
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define rep(i, n) FOR(i, 0, n)
#define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--)
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())
#define FI first
#define SE second
using namespace std;

//  types
typedef pair<int, int> P;
typedef pair<ll, int> Pl;
typedef pair<ll, ll> Pll;
typedef pair<double, double> Pd;
 
// constants
const int inf = 1e9;
const ll linf = 1LL << 50;
const double EPS = 1e-10;
const int mod = 1e9 + 7;

// solve
template <class T>bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;}
template <class T>bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;}
template <typename T> istream &operator>>(istream &is, vector<T> &vec){for(auto &v: vec)is >> v; return is;}

ll dp[101][30001];

int main(int argc, char const* argv[])
{
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int n, V;
  cin >> n >> V;
  vector<ll> c(n), cs(n);
  cin >> c;
  rep(i, n){
    cs[i] = c[i];
    if(i > 0)cs[i] += cs[i-1];
  }
  if(n >= V){
    cout << cs[n-1] << endl;
    return 0;
  }
  V -= n;
  int at = 0;
  double mini = (double)cs[0];
  FOR(i, 1, n){
    double tmp = (double)cs[i] / (i + 1);
    if(mini > tmp){
      mini = tmp;
      at = i;
    }
  }

  const int v = 20000;
  ll res = cs[n-1];
  ll t = max(0, (V - v) / (at + 1));
  res += t * cs[at];
  int R = V - t * (at + 1);
  for(int i = 0; i <= n; i++){
    for(int j = 0; j <= R; j++){
      dp[i][j] = linf;
    }
  }
  dp[0][0] = 0;
  for(int i = 0; i < n; i++){
    for(int j = 0; j <= R; j++){
      dp[i+1][j] = dp[i][j];
      if(j - i - 1 >= 0){
        dp[i+1][j] = min(dp[i+1][j], dp[i+1][j-i-1] + cs[i]);
      }
    }
  }
  res += dp[n][R];
  cout << res << endl;
	return 0;
}