#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int t = 1;
  while (t--) {
    int n, m, x, y;
    cin >> n >> m >> x >> y;
    bool a[n + 1][m + 1];
    for (int i = 1; i <= n; i++)
      for (int j = 1; j <= m; j++) a[i][j] = 0;
    a[x][y] = 1;
    cout << x << ' ' << y << '\n';
    if (a[1][y] != 1) {
      a[1][y] = 1;
      cout << 1 << ' ' << y << '\n';
    }
    if (a[1][1] != 1) {
      a[1][1] = 1;
      cout << 1 << ' ' << 1 << '\n';
    }
    for (int i = 1; i <= n; i++) {
      if (i & 1) {
        for (int j = 1; j <= m; j++) {
          if (a[i][j] != 1) {
            cout << i << ' ' << j << '\n';
            a[i][j] = 1;
          }
        }
      } else {
        for (int j = m; j >= 1; j--) {
          if (a[i][j] != 1) {
            cout << i << ' ' << j << '\n';
            a[i][j] = 1;
          }
        }
      }
    }
  }
  return 0;
}
