#include<bits/stdc++.h>
using namespace std;
const int N = 25;
long long a[N][N];
int main(){
    int n, m, x, y;
    cin >> n >> m >> x >> y;
    int dx[] = {0, 2, 1, -1, -2, -2, -1, 1, 2};
    int dy[] = {0, 1, 2, 2, 1, -1, -2, -2, -1};
    for (int i = 0; i <= n; i++){
        for (int j = 0; j <= m; j++){
            int f = 0;
            for (int k = 0; k <= 8; k++){
                if (dx[k]+x == i && dy[k]+y == j){
                    f = 1;
                    break;
                }
            }
            if (f) {
                a[i][j] = 0;
            }else if (i == 0 || j == 0){
                a[i][j] = 1;
            }else{
                a[i][j] = a[i][j-1] + a[i-1][j];
            }
        }
    }
    cout << a[n][m];
    return 0;
}

60分，WA，求调，谢谢