#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long int n, i, j, k, m, c, x, y;
  long long int count = 0;
  cin >> n >> m >> x >> y;
  i = x;
  j = y;
  cout << x << " " << y << "\n";
  j++;
  do {
    do {
      cout << i << " " << j << "\n";
      count++;
      j++;
      if (j > m) j = j - m;
      if (count >= n * m) {
        cout << "\n";
        cout << 1;
        ;
        break;
      }
    } while (j != y);
    y--;
    if (y <= 0) y = y + m;
    j = y;
    i++;
    if (i > n) i = i - n;
    if (count >= n * m) {
      cout << "\n";
      cout << 1;
      ;
      break;
    }
  } while (i != x);
}
