#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long int t = 1, i, j, k, l;
  while (t--) {
    long long int n, m, x, y;
    cin >> n >> m >> x >> y;
    vector<pair<long long int, long long int> > v;
    v.push_back({x, y});
    for (i = 1; i <= m; i++)
      if (i != y) v.push_back({x, i});
    k = 1;
    for (i = x - 1; i >= 1; i--) {
      if (k & 1)
        for (j = m; j >= 1; j--) v.push_back({i, j});
      else
        for (j = 1; j <= m; j++) v.push_back({i, j});
      k++;
    }
    for (i = x + 1; i <= n; i++) {
      if (k & 1)
        for (j = m; j >= 1; j--) v.push_back({i, j});
      else
        for (j = 1; j <= m; j++) v.push_back({i, j});
      k++;
    }
    for (auto r : v) cout << r.first << " " << r.second << "\n";
    cout << "\n";
  }
  return 0;
}
