#include <bits/stdc++.h>
using namespace std;
using ll = long long;
template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
  os << "[";
  for (int i = 0; i < v.size(); ++i) {
    os << v[i];
    if (i != v.size() - 1) os << ", ";
  }
  os << "]\n";
  return os;
}
int main() {
  int n, m;
  cin >> n >> m;
  int x, y;
  cin >> x >> y;
  set<pair<int, int>> used;
  used.insert({x, y});
  used.insert({x, 1});
  cout << x << " " << y << "\n" << x << " " << 1 << "\n";
  for (int ny = 1; ny <= m; ny++) {
    if (ny % 2) {
      for (int nx = 1; nx <= n; nx++) {
        if (used.count({nx, ny}) < 1) {
          cout << nx << " " << ny << "\n";
        }
      }
    } else {
      for (int nx = n; nx >= 1; nx--) {
        if (used.count({nx, ny}) < 1) {
          cout << nx << " " << ny << "\n";
        }
      }
    }
  }
}
