#include <bits/stdc++.h>
using namespace std;
const int mn = 105;

int l[mn], p[mn];
int dp[mn][mn];
int main()
{
	int n, m;
	scanf("%d %d", &n, &m);
	for (int i = 1; i <= n; i++)
		scanf("%d", &l[i]);
		
	p[1] = m;
	for (int i = 2; i <= n; i++)	// 連續第 i 天的進食量
		p[i] = p[i - 1] * 2 / 3;
	
	// dp[i][j] 第i天進食量為j時的最大答案
	dp[1][0] = 0;
	dp[1][1] = min(p[1], l[1]);
	dp[2][0] = max(dp[1][0], dp[1][1]);
	dp[2][1] = min(p[1], l[2]);
	dp[2][2] = dp[1][1] + min(p[2], l[2]);
	for (int i = 3; i <= n; i++)
	{
		for (int j = 0; j <= i; j++)
		{
			int a = dp[i - 1][max(j - 1, 0)] + min(p[j], l[i]);		// 不餓 連續吃到 j
			int b = dp[i - 2][j] + min(p[j], l[i]);		// 餓一天 前天是 j
			dp[i][j] = max(a, b);
		}
		
		// 餓兩天
		int ma = 0;
		for (int j = 0; j <= i - 3; j++)
			ma = max(ma, dp[i - 3][j]);
		dp[i][1] = max(dp[i][1], ma + min(p[1], l[i]));
	}
	
	int ans = 0;
	for (int j = 0; j <= n; j++)
		ans = max(ans, dp[n][j]);
	printf("%d\n", ans);
	
	return 0;
}