#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, m, x, i, j, k, y;
  cin >> n >> m >> x >> y;
  cout << x << " " << y << endl;
  for (i = 1; i <= m; i++) {
    if (i != y) {
      cout << x << " " << i << endl;
    }
  }
  j = x - 1;
  k = m;
  while (j > 0) {
    if (k == m) {
      for (i = m; i >= 1; i--) cout << j << " " << i << endl;
      k = 1;
    } else {
      for (i = 1; i <= m; i++) cout << j << " " << i << endl;
      k = m;
    }
    j--;
  }
  j = x + 1;
  if (x & 1)
    k = m;
  else
    k = 1;
  while (j <= n) {
    if (k == m) {
      for (i = m; i >= 1; i--) cout << j << " " << i << endl;
      k = 1;
    } else {
      for (i = 1; i <= m; i++) cout << j << " " << i << endl;
      k = m;
    }
    j++;
  }
}
