#include <bits/stdc++.h>
using namespace std;
void p(int x, int y) { cout << x << " " << y << endl; }
int main() {
  int n, m, x, y;
  cin >> n >> m >> x >> y;
  vector<array<int, 2>> bad;
  p(x, y);
  bad.push_back({x, y});
  y = 1;
  p(x, y);
  bad.push_back({x, y});
  x = 1;
  p(x, y);
  bad.push_back({x, y});
  bool going_right = true;
  for (auto y = 1; y <= m; ++y) {
    for (auto z = 0; z < n; ++z) {
      auto x = going_right ? z + 1 : n - z;
      array<int, 2> po = {x, y};
      if (find(bad.begin(), bad.end(), po) != bad.end()) continue;
      p(x, y);
    }
    going_right = !going_right;
  }
}
