using namespace std;
long long tx[9]={0,-2,-1,1,2,2,1,-1,-2};
long long ty[9]={0,-1,-2,-2,-1,1,2,2,1};
long long n,m,x,y;
int main()
{
	scanf("%lld%lld%lld%lld",&n,&m,&x,&y);
	n++;m++;x++;y++;
	long long a[n+1][m+1],f[n+1][m+1];
	memset(a,0,sizeof(a));
	memset(f,0,sizeof(f));
	for(long long i=0;i<=8;i++)
	{
		if((x+tx[i])%(n+1)!=0&&(y+ty[i])%(m+1)!=0)
		f[x+tx[i]][y+ty[i]]=1;
	}
	a[0][1]=1;
	for(long long i=1;i<=n;i++)
	{
		for(long long j=1;j<=m;j++)
		{
			a[i][j]=abs(f[i][j]-1)*(a[i-1][j]+a[i][j-1]);
		}
	}
	printf("%lld",a[n][m]);
	return 0;
}