#include <bits/stdc++.h>
const int maxn = 1e5 + 5;
const long long mod = 1e9 + 7;
const int MAXN = 4e6 + 5;
using namespace std;
int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);
  std::cout.tie(0);
  int n, m, x, y, cnt = 0;
  cin >> n >> m >> x >> y;
  cout << x << " " << y << endl;
  for (int i = 1; i <= m; i++)
    if (i != y) cout << x << " " << i << endl;
  int flag = 1;
  for (int i = 1; i <= n; i++)
    if (i != x) {
      if (flag == 1) {
        for (int j = m; j >= 1; j--) cout << i << " " << j << endl;
      } else {
        for (int j = 1; j <= m; j++) cout << i << " " << j << endl;
      }
      flag = -flag;
      cnt++;
    }
  cnt++;
  return 0;
}
