#include <iostream>
#include <vector>

using namespace std;

int MAX_CALORIES;

// Max calories from position i to the end
// We've been eating for m hours straight
// Rest is whether we rested (instead of eating) last hour
int Solve(const vector<int>& calories, vector<vector<vector<int> > >& Memo, int i, int m, int rest){
  if(i >= calories.size())
    return 0;
  if(Memo[i][m][rest] != -1)
    return Memo[i][m][rest];
  int calories_this_hour = MAX_CALORIES;
  for(int j = 0; j < m; j++)
    calories_this_hour = calories_this_hour * 2 / 3;
  int eat = min(calories[i], calories_this_hour);

  eat = eat + Solve(calories, Memo, i+1, m+1, 0);
  
  int new_m;
  if(rest == 0)
    new_m = max(m-1,0);
  else
    new_m = 0;
  int stop = Solve(calories, Memo, i+1, new_m, 1);
  int best = max(eat, stop);
  Memo[i][m][rest] = best;
  return best;
}

int main(){
  int n;
  cin >> n;
  cin >> MAX_CALORIES;
  vector<int> calories(n);
  for(int i = 0; i < n; i++)
    cin >> calories[i];

  vector<vector<vector<int> > > Memo(n);
  for(int i = 0; i < Memo.size(); i++){
    Memo[i].resize(n+1);
    for(int j = 0; j <= n; j++)
      Memo[i][j].resize(2,-1);
  }
  
  int best = Solve(calories, Memo, 0,0, 1);
  cout << best << endl;

  return 0;
}