#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 7;
int n, m, sx, sy;
int main() {
  cin >> n >> m >> sx >> sy;
  int cnt = 0;
  for (int i = sx; i < n + 1; ++i) {
    if (i == sx) {
      for (int j = sy; j <= m; ++j) {
        cout << i << " " << j << endl;
      }
      for (int j = sy - 1; j > 0; --j) {
        cout << i << " " << j << endl;
      }
      continue;
    }
    if (cnt % 2 == 0) {
      for (int j = 1; j <= m; ++j) {
        cout << i << " " << j << endl;
      }
    } else
      for (int j = m; j > 0; --j) {
        cout << i << " " << j << endl;
      }
    cnt++;
  }
  for (int i = sx - 1; i > 0; --i) {
    if (cnt % 2 == 0)
      for (int j = 1; j <= m; ++j) {
        cout << i << " " << j << endl;
      }
    else
      for (int j = m; j > 0; --j) {
        cout << i << " " << j << endl;
      }
    cnt++;
  }
  return 0;
}
