#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n, m, x, y, i;
  cin >> n >> m >> x >> y;
  cout << x << " " << y << endl;
  int k = x + 1;
  int p = x - 1;
  for (i = 1; i < m + 1; i++) {
    if (i != y) cout << x << " " << i << endl;
  }
  int jj = 1;
  while (k <= n) {
    if (jj == 0) {
      for (i = 1; i < m + 1; i++) {
        cout << k << " " << i << endl;
      }
      jj = 1;
    } else {
      for (i = m; i >= 1; i--) {
        cout << k << " " << i << endl;
      }
      jj = 0;
    }
    k++;
  }
  while (p >= 1) {
    if (jj == 0) {
      for (i = 1; i < m + 1; i++) {
        cout << p << " " << i << endl;
      }
      jj = 1;
    } else {
      for (i = m; i >= 1; i--) {
        cout << p << " " << i << endl;
      }
      jj = 0;
    }
    p--;
  }
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int t;
  t = 1;
  while (t--) {
    solve();
  }
}
