#include <bits/stdc++.h>
using namespace std;
const int N = 110;
int n, m, sx, sy;
int main() {
  cin >> n >> m >> sx >> sy;
  for (int i = sy; i <= m; i++) cout << sx << ' ' << i << endl;
  for (int i = sy - 1; i >= 1; i--) cout << sx << ' ' << i << endl;
  int cnt = 1;
  int line = 1;
  while (cnt < n) {
    if (line == sx) line++;
    if (cnt % 2 == 1) {
      for (int j = 1; j <= m; j++) cout << line << ' ' << j << endl;
      cnt++;
      line++;
    } else {
      for (int j = m; j >= 1; j--) cout << line << ' ' << j << endl;
      cnt++;
      line++;
    }
  }
  return 0;
}
