#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m;
  cin >> n >> m;
  int x, y;
  cin >> x >> y;
  cout << x << " " << y << endl;
  for (int i = y; i > 0; i--) cout << 1 << " " << i << endl;
  for (int i = y + 1; i <= m; i++) cout << 1 << " " << i << endl;
  for (int i = 2; i <= n; i++) {
    if (i % 2 == 0) {
      for (int j = m; j > 0; j--)
        if (i != x || j != y) cout << i << " " << j << endl;
    } else {
      for (int j = 1; j <= m; j++)
        if (i != x || j != y) cout << i << " " << j << endl;
    }
  }
}
