#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, M, x, y;
  cin >> N >> M >> x >> y;
  cout << x << " " << y << endl;
  cout << 1 << " " << y << endl;
  for (int i = 1; i <= N; i++)
    for (int j = (i % 2) ? 1 : M; j <= M && j; j += i % 2 * 2 - 1)
      if (!((i == x && j == y) || (i == 1 && j == y)))
        cout << i << " " << j << endl;
}
