#include<bits/stdc++.h>
using namespace std;
long long n,m,px,py,ans;
long long a[21][21];
void go(int x,int y)
{
	if(x==n&&y==m)
	{
		ans++;
		return;
	}
	if(x+1<=n&&a[x+1][y]==0)
	{
		go(x+1,y);
	}
	if(y+1<=m&&a[x][y+1]==0)
	{
		go(x,y+1);
	}
}
int main()
{
	cin>>n>>m;
	cin>>px>>py;
	a[px][py]=1;
	if(px-2>=0&&py-1>=0) a[px-2][py-1]=1;
	if(px-1>=0&&py-2>=0) a[px-1][py-2]=1;
	if(px+1<=n&&py-2>=0) a[px+1][py-2]=1;
	if(px+2<=n&&py-1>=0) a[px+2][py-1]=1;
	if(px+2<=n&&py+1<=m) a[px+2][py+1]=1;
	if(px+1<=n&&py+2<=m) a[px+1][py+2]=1;
	if(px-1>=0&&py+2<=m) a[px-1][py+2]=1;
	if(px-2>=0&&py+1<=m) a[px-2][py+1]=1;
	go(0,0);
	cout<<ans;
	return 0;
} 

3，4点TLE了