#include<cstdio>
using namespace std;
int n,a,b;
int kd;// empty single
int ks;// empty double
int hk;// half empty
int ans=0;
int main(){
	freopen("RT.in","r",stdin);
	freopen("RT.out","w",stdout);
	scanf("%d%d%d",&n,&a,&b);
	kd=a;ks=b;
	int x;
	while(n--){
		scanf("%d",&x);
		if(x==1){
			if(kd>0||ks>0){
				if(kd>0)
					kd--;
				else{
					ks--;
					hk++;
				}
			}
			else{
				if(hk>0)
					hk--;
				else
					ans++;
			}
		}
		else{
			if(ks>0)
				ks--;
			else
				ans+=2;
		}
	}
	printf("%d",ans);
	return 0;
}