#include <bits/stdc++.h>
using namespace std;
const int mod = 1000000007;
void solve() {
  int n, m, Sx, Sy;
  cin >> n >> m >> Sx >> Sy;
  for (int i = Sy; i <= m; i++) {
    cout << Sx << " " << i << "\n";
  }
  for (int i = Sy - 1; i >= 1; i--) {
    cout << Sx << " " << i << "\n";
  }
  int cnt = 0;
  for (int i = Sx - 1; i >= 1; i--) {
    cnt++;
    if (cnt % 2 == 1) {
      for (int j = 1; j <= m; j++) {
        cout << i << " " << j << "\n";
      }
    } else {
      for (int j = m; j >= 1; j--) {
        cout << i << " " << j << "\n";
      }
    }
  }
  for (int i = Sx + 1; i <= n; i++) {
    cnt++;
    if (cnt % 2 == 1) {
      for (int j = 1; j <= m; j++) {
        cout << i << " " << j << "\n";
      }
    } else {
      for (int j = m; j >= 1; j--) {
        cout << i << " " << j << "\n";
      }
    }
  }
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int t = 1;
  while (t--) {
    solve();
  }
}
