#include <bits/stdc++.h>
using namespace std;
int a[101][101];
int main() {
  int n, m, x, y;
  cin >> n >> m >> x >> y;
  cout << x << " " << y << endl;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++) a[i][j] = 1;
  a[x - 1][y - 1] = 0;
  a[0][y - 1] = 0;
  a[0][0] = 0;
  cout << 1 << " " << y << endl;
  cout << 1 << " " << 1 << endl;
  for (int i = 0; i < n; i++) {
    if (i % 2 == 0) {
      for (int j = 0; j < m; j++) {
        if (a[i][j] != 0) {
          cout << i + 1 << " " << j + 1 << endl;
          a[i][j] = 0;
        }
      }
    } else {
      for (int j = m - 1; j >= 0; j--) {
        if (a[i][j] != 0) {
          cout << i + 1 << " " << j + 1 << endl;
          a[i][j] = 0;
        }
      }
    }
  }
}
