#include<fstream>
using namespace std;
ifstream cin("RT.in");
ofstream cout("RT.out");
int n,a,b,ans=0,i,now,kong=0;
int main()
{
	cin>>n>>a>>b;
	for(i=1;i<=n;i++)
	{
		cin>>now;
		if(now==1)
		{
			if(a>0)a--;
			else if(b>=1)b-=1,kong++;
			else if(b==0&&kong>0)kong--;
			else ans++;
		}
		if(now==2)
		{
			if(b>=1)b-=1;
			else ans+=2;
		}
	}
	cout<<ans<<endl;
	cin.close();
	cout.close();
	return 0;
}