超时，求解

#include<iostream>
using namespace std;
int sum;
int f(int x,int y)
{
	if(x>y)
	{
		sum+=y*4;
		x-=y;
	}
	if(x<y)
	{
		sum+=x*4;
		y-=x;
	}
	if(x==y)
	{
		sum+=x*4;
		x-=y;
		y-=y;
	}
	if(x==0&&y==0)
	{
		return 0;
	}
	else
	{
		f(x,y);
	}
}
int main()
{
	long long x,y;
	cin>>x>>y;
	f(x,y);
	cout<<sum;
	return 0;
}
//100%超时