#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, M, x, y;
  cin >> N >> M >> x >> y;
  x--;
  y--;
  cout << x + 1 << " " << y + 1 << endl;
  for (int i = 1; i < x; i++) cout << i + 1 << " " << y + 1 << endl;
  for (int i = x + 1; i < N; i++) cout << i + 1 << " " << y + 1 << endl;
  cout << 1 << " " << y + 1 << endl;
  int uneven = 0;
  for (int j = 0; j < M; j++) {
    if (j == y) {
      uneven = 1;
      continue;
    }
    if (j % 2 == uneven) {
      for (int i = 0; i < N; i++) {
        cout << i + 1 << " " << j + 1 << endl;
      }
    }
    if (j % 2 != uneven) {
      for (int i = N - 1; i > -1; i--) {
        cout << i + 1 << " " << j + 1 << endl;
      }
    }
  }
}
