#include <bits/stdc++.h>
using namespace std;
int n, m, a, b, x, y;
void afis(int r, bool ok) {
  if (ok == 1) {
    for (int i = m; i >= 1; i--) {
      if (r != a || (r == a && i != b)) cout << r << ' ' << i << '\n';
    }
  } else if (ok == 0) {
    for (int i = 1; i <= m; i++) {
      if (r != a || (r == a && i != b)) cout << r << ' ' << i << '\n';
    }
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> m >> a >> b;
  cout << a << ' ' << b << '\n';
  cout << 1 << ' ' << b << '\n';
  for (int i = 1; i <= m; i++) {
    if (i != b) cout << 1 << ' ' << i << '\n';
  }
  bool ok = 1;
  x = 2;
  while (x <= n) {
    afis(x, ok);
    x++;
    ok = !ok;
  }
  return 0;
}
