#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  long long t, n, i, j, k, l, m, a, b;
  cin >> n >> m >> a >> b;
  cout << a << " " << b << "\n";
  for (i = b - 1; i >= 1; i--) {
    cout << a << " " << i << "\n";
  }
  for (i = b + 1; i <= m; i++) cout << a << " " << i << "\n";
  for (i = a - 1; i >= 1; i--) {
    if ((a - i) & 1) {
      for (j = m; j >= 1; j--) cout << i << " " << j << "\n";
    } else {
      for (j = 1; j <= m; j++) cout << i << " " << j << "\n";
    }
  }
  for (i = a + 1; i <= n; i++) {
    if (i & 1) {
      for (j = 1; j <= m; j++) cout << i << " " << j << "\n";
    } else {
      for (j = m; j >= 1; j--) cout << i << " " << j << "\n";
    }
  }
  return 0;
}
