#include<iostream>
using namespace std;
int check(int n,int m,int x,int y);
int main()
{
    int n,m;
    cin>>n>>m;
    long long a[n+1][m+1]={0};
    for(int i=0;i<=n;i++)
    {
    a[i][0]=1;
    }
    for(int i=0;i<=m;i++)
    {
    a[0][i]=1;
    }
    int x,y;
    cin>>x>>y;
    for(int i=1;i<=n;i++)
        for(int j=1;j<=m;j++)
        {
        a[i][j]=a[i-1][j]+a[i][j-1];
        if(!check(i,j,x,y))
        {a[i][j]=0;}
        }
    cout<<a[n][m];
}
 
int check(int n,int m,int x,int y)
{
	if(n==x-2&&m==y+1){return 0;}
	if(n==x+2&&m==y+1){return 0;}
	if(n==x-2&&m==y-1){return 0;}
	if(n==x+2&&m==y-1){return 0;}
	if(n==x-1&&m==y+2){return 0;}
	if(n==x-1&&m==y-2){return 0;}
	if(n==x+1&&m==y+2){return 0;}
	if(n==x+1&&m==y-2){return 0;}
	if(n==x&&m==y){return 0;}
}```