#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n, m;
  cin >> n >> m;
  int x, y;
  cin >> x >> y;
  x--, y--;
  vector<vector<int> > vis(n, vector<int>(m));
  vector<int> row;
  row.push_back(x);
  for (int i = 0; i < n; i++) {
    if (i == x) continue;
    row.push_back(i);
  }
  bool first = true;
  int we = 1;
  cout << x + 1 << " " << y + 1 << "\n";
  for (int i = 0; i < n; i++) {
    if (we) {
      for (int j = 0; j < m; j++) {
        if (i == 0 && j == y) {
          continue;
        }
        cout << row[i] + 1 << " " << j + 1 << "\n";
      }
      we = 0;
    } else {
      for (int j = m - 1; j >= 0; j--) {
        cout << row[i] + 1 << " " << j + 1 << "\n";
      }
      we = 1;
    }
  }
  return 0;
}
