#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, m, sx, sy;
  cin >> n >> m >> sx >> sy;
  for (int i = sy; i >= 1; i--) cout << sx << " " << i << endl;
  for (int i = sy + 1; i <= m; i++) cout << sx << " " << i << endl;
  int co = 0;
  for (int i = sx - 1; i >= 1; i--, co++) {
    if (co % 2 == 0) {
      for (int j = m; j >= 1; j--) cout << i << " " << j << endl;
    } else {
      for (int j = 1; j <= m; j++) cout << i << " " << j << endl;
    }
  }
  if (co % 2 != 0) {
    int co1 = 0;
    for (int i = sx + 1; i <= n; i++, co1++) {
      if (co1 % 2 == 0)
        for (int j = 1; j <= m; j++) cout << i << " " << j << endl;
      else
        for (int j = m; j >= 1; j--) cout << i << " " << j << endl;
    }
  } else {
    int co1 = 0;
    for (int i = sx + 1; i <= n; i++, co1++) {
      if (co1 % 2 == 0)
        for (int j = m; j >= 1; j--) cout << i << " " << j << endl;
      else
        for (int j = 1; j <= m; j++) cout << i << " " << j << endl;
    }
  }
  return 0;
}
