#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n, m, x, y;
  cin >> n >> m >> x >> y;
  set<pair<int, int>> check;
  vector<pair<int, int>> a;
  check.insert(make_pair(x, y));
  a.push_back(make_pair(x, y));
  x = 1;
  check.insert(make_pair(x, y));
  a.push_back(make_pair(x, y));
  x = 1, y = 1;
  while (1) {
    if ((x % 2 == 1 && y != m + 1) || (x % 2 == 0 && y != 0)) {
      int sz1 = check.size();
      check.insert(make_pair(x, y));
      int sz2 = check.size();
      if (sz1 != sz2) a.push_back(make_pair(x, y));
      if (x % 2)
        y++;
      else
        y--;
      continue;
    }
    if (x % 2) {
      y--;
    } else {
      y++;
    }
    x++;
    if (x == n + 1) break;
    a.push_back(make_pair(x, y));
    check.insert(make_pair(x, y));
  }
  for (int i = 0; i < a.size(); i++) {
    cout << a[i].first << " " << a[i].second << "\n";
  }
  return 0;
}
