rt

#include<bits/stdc++.h>
using namespace std;
long long f[1011][1011],a[1011][1011],m,n,x,y,i,j;
int main(){
    cin>>n>>m>>x>>y;
    f[x][y]=1; 
    f[x+2][y+1]=1; 
    f[x+2][y-1]=1; 
    f[x+1][y+2]=1; 
    f[x+1][y-2]=1; 
    f[x-1][y+2]=1; 
    f[x-1][y-2]=1; 
    f[x-2][y+1]=1;
    f[x-2][y-1]=1; 
    for(i=0;i<=n;++i)
        for(j=0;j<=m;++j)
        {
          if(f[i][j]==1) a[i][j]=0;
          else if(i==0 && j==0) a[i][j]=1; 
          else if(i==0 && j!=0) a[i][j]=a[i][j-1]; 
          else if(i!=0 && j==0) a[i][j]=a[i-1][j]; 
          else a[i][j]=a[i-1][j]+a[i][j-1]; 
      }
      cout<<a[n][m];
	  return 0; 
  }