#include <iostream> using namespace std; long long a , b , n , m , x[23][23] , ma[23][23]; void work(long long x,long long y) { ma[x][y] = true; ma[x - 1][y - 2] = true; ma[x - 2][y - 1] = true; ma[x - 2][y + 1] = true; ma[x - 1][y + 2] = true; ma[x + 1][y - 2] = true; ma[x + 2][y - 1] = true; ma[x + 2][y + 1] = true; ma[x + 1][y + 2] = true; } int main() { cin >> n >> m >> a >> b; a++;b++;n++;m++; work(a , b); x[1][1] = 1; for(int i = 1;i <= n;i++){ for(int j = 1;j <= m;j++){ if(i == 1 && j == 1)continue; if(ma[i][j] == 0) x[i][j] = x[i - 1][j] + x[i][j - 1]; } } cout << x[n][m]; return 0; }