#include <bits/stdc++.h>
using namespace std;
void solve() {
  long long int n, m, sx, sy, flag = 1;
  cin >> n >> m >> sx >> sy;
  long long int a = sx;
  cout << sx << " " << sy << endl;
  for (long long int i = 1; i <= m; i++) {
    if (i != sy) {
      cout << sx << " " << i << endl;
    }
  }
  a--;
  while (a > 0) {
    if (flag == 1 && a > 0) {
      for (long long int i = m; i >= 1; i--) {
        cout << a << " " << i << endl;
      }
      flag = 0;
      a--;
    } else if (flag == 0 && a > 0) {
      for (long long int i = 1; i <= m; i++) {
        cout << a << " " << i << endl;
      }
      flag = 1;
      a--;
    } else if (a == 0)
      break;
  }
  a = sx + 1;
  while (a <= n) {
    if (flag == 1 && a <= n) {
      for (long long int i = m; i >= 1; i--) {
        cout << a << " " << i << endl;
      }
      flag = 0;
      a++;
    } else if (flag == 0 && a <= n) {
      for (long long int i = 1; i <= m; i++) {
        cout << a << " " << i << endl;
      }
      flag = 1;
      a++;
    } else if (a > n)
      break;
  }
}
void testcase() {
  int t;
  cin >> t;
  while (t--) {
    solve();
  }
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  solve();
}
