#include <bits/stdc++.h>
using namespace std;
int main() {
  long long xmax, ymax, sx, sy, i, j;
  cin >> xmax >> ymax >> sx >> sy;
  cout << sx << ' ' << sy << endl;
  for (i = sx - 1; i >= 1; i--) cout << i << ' ' << sy << endl;
  i++;
  for (j = sy + 1; j <= ymax; j++) cout << i << ' ' << j << endl;
  j--;
  for (j = sy - 1; j >= 1; j--) cout << i << ' ' << j << endl;
  j++;
  for (i = 2; i <= xmax; i++) {
    if (i % 2 == 0) {
      for (j = 1; j <= ymax; j++) {
        if (i <= sx && j == sy)
          continue;
        else
          cout << i << ' ' << j << endl;
      }
      j--;
    } else {
      for (j = ymax; j >= 1; j--) {
        if (i <= sx && j == sy)
          continue;
        else
          cout << i << ' ' << j << endl;
      }
      j++;
    }
  }
  return 0;
}
