#include <bits/stdc++.h>
using namespace std;
int n, m;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int x, y;
  while (cin >> n >> m >> x >> y) {
    bool flag = 0;
    cout << x << ' ' << y << endl;
    for (int i = 1; i <= n; ++i) {
      if (i != x) {
        cout << i << ' ' << y << endl;
      }
    }
    for (int j = 1; j <= m; ++j) {
      if (j != y) {
        if (flag) {
          for (int i = 1; i <= n; ++i) {
            cout << i << ' ' << j << endl;
          }
        } else {
          for (int i = n; i >= 1; --i) {
            cout << i << ' ' << j << endl;
          }
        }
        flag = !flag;
      }
    }
  }
}
