#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n, m, x, y, i, j, k, l;
  cin >> n >> m >> x >> y;
  cout << x << " " << y << "\n";
  for (i = 1; i <= m; i++)
    if (i != y) cout << x << " " << i << "\n";
  int c;
  for (i = 1, j = m; i <= n; i++)
    if (i != x)
      for (k = 1; k <= m; k++) {
        cout << i << " " << j << "\n";
        if (j == m)
          c = -1;
        else if (j == 1)
          c = 1;
        if (k != m) j += c;
      }
  return 0;
}
