#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, x, y, l, r, t, b, s = 1, u = 1;
  cin >> n >> m >> x >> y;
  l = r = y, t = b = x, ++b;
  for (int i = 0; i < n * m; ++i) {
    if (!t)
      if (l)
        cout << b << " " << l--;
      else if (r != m)
        cout << b << " " << ++r;
    if (!t && !l && r == m && !u)
      r = l, ++b, u = 1;
    else if (!t && !l && r == m && u)
      u = 0, l = r, ++b;
    if (l && t)
      cout << t << " " << l--;
    else if (r != m && t)
      cout << t << " " << ++r;
    if (!l && r == m && s && u)
      l = r, --t, u = 0;
    else if (!l && r == m && s && !u)
      u = 1, r = l, --t;
    if (!t) s = 0;
    cout << "\n";
  }
  return 0;
}
