#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n, m, x, y;
  cin >> n >> m >> x >> y;
  --x, --y;
  vector<pair<int, int> > ans;
  vector<bool> vis(n, 0);
  vis[x] = 1;
  for (int i = y; i < m; ++i) ans.push_back({x, i});
  for (int i = y - 1; ~i; --i) ans.push_back({x, i});
  bool poz = 1;
  for (int i = 0; i < n; ++i) {
    if (vis[i]) continue;
    if (poz) {
      for (int j = 0; j < m; ++j) ans.push_back({i, j});
    } else {
      for (int j = m - 1; ~j; --j) ans.push_back({i, j});
    }
    poz ^= 1;
  }
  for (auto z : ans) cout << z.first + 1 << ' ' << z.second + 1 << '\n';
}
