#include <cstdio>
#include <vector>
#include <algorithm>
#include <iostream>

using namespace std;

int main()
{
	int n, a, b, now = 0, ans = 0;
	freopen("RT.in", "r", stdin);
	freopen("RT.out", "w", stdout);
	
	scanf("%d%d%d", &n, &a, &b);
	
	for(int i = 1; i <= n; i++)
	{
		int c;
		
		scanf("%d", &c);
		
		if(c == 1)
		{
			if(a >= 1)
			{
				a--;
			}
			else if(b >= 1)
			{
				b--;
				now++;
			}
			else if(now >= 1)
			{
				now--;
			}
			else
			{
				ans++;
			}
		}
		else
		{
			if(b >= 1)
			{
				b--;
			}
			else
			{
				ans += 2;
			}
		}
	}
	
	printf("%d\n", ans);
	
	return 0;
}