#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n, m, xx, yy;
  cin >> n >> m >> xx >> yy;
  cout << xx << " " << yy << '\n';
  for (int i = 1; i <= m; i++)
    if (i != yy) cout << xx << " " << i << '\n';
  bool rev = true;
  for (int i = 1; i <= n; i++)
    if (i != xx) {
      if (rev) {
        for (int j = m; j >= 1; j--) cout << i << " " << j << '\n';
        rev = false;
      } else {
        for (int j = 1; j <= m; j++) cout << i << " " << j << '\n';
        rev = true;
      }
    }
}
int main() {
  cin.tie(0);
  cout.tie(0);
  solve();
  return 0;
}
