#include <bits/stdc++.h>
using namespace std;
const int maxn = 200010;
const long long Mod = 998244353;
int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);
  ;
  int n, m, x, y;
  cin >> n >> m >> x >> y;
  cout << x << ' ' << y << endl;
  for (int i = y + 1; i <= m; i++) cout << x << ' ' << i << endl;
  for (int i = y - 1; i >= 1; i--) cout << x << ' ' << i << endl;
  int f = 0;
  for (int i = 1; i <= n; i++) {
    if (i == x) continue;
    if (f == 0) {
      for (int j = 1; j <= m; j++) cout << i << ' ' << j << endl;
    } else {
      for (int j = m; j >= 1; j--) cout << i << ' ' << j << endl;
    }
    f = 1 - f;
  }
  return 0;
}
