#include <bits/stdc++.h>
using namespace std;
long long int mod = 1000000007;
void solve() {
  long long int n, m, x, y;
  cin >> n >> m >> x >> y;
  cout << x << " " << y << endl;
  for (long long int i = 1; i < y; i++) {
    cout << x << " " << i << endl;
  }
  for (long long int i = y + 1; i <= m; i++) {
    cout << x << " " << i << endl;
  }
  bool flag = false;
  for (int i = 1; i <= n; i++) {
    if (i == x) {
      continue;
    }
    if (!flag) {
      for (long long int j = m; j >= 1; j--) {
        cout << i << " " << j << endl;
      }
      flag = true;
    } else {
      for (long long int j = 1; j <= m; j++) {
        cout << i << " " << j << endl;
      }
      flag = false;
      ;
    }
  }
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  solve();
  return 0;
}
