#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n, m;
  int x, y;
  int z = 1;
  cin >> n >> m;
  cin >> x >> y;
  cout << x << " " << y << "\n";
  cout << 1 << " " << y << "\n";
  for (int i = 1; i <= n; i++) {
    vector<pair<int, int>> v;
    for (int j = 1; j <= m; j++) {
      if ((i == x && j == y) || (i == 1 && j == y)) continue;
      v.push_back({i, j});
    }
    if (z) {
      reverse(v.begin(), v.end());
    }
    for (auto it : v) {
      cout << it.first << " " << it.second << "\n";
    }
    z ^= 1;
  }
}
int main() {
  ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL);
  solve();
  return 0;
}
