#include <bits/stdc++.h>
using namespace std;
int main() {
  pair<int, int> a[3];
  for (int i = 0; i < 3; i++) cin >> a[i].first >> a[i].second;
  sort(a, a + 3);
  int u = max({a[0].second, a[1].second, a[2].second});
  int b = min({a[0].second, a[1].second, a[2].second});
  int ans = a[2].first - a[0].first + u - b + 1;
  cout << ans << '\n';
  for (int i = b; i <= u; i++) printf("%d %d\n", a[1].first, i);
  for (int i = a[0].first; i < a[1].first; i++)
    printf("%d %d\n", i, a[0].second);
  for (int i = a[2].first; i > a[1].first; i--)
    printf("%d %d\n", i, a[2].second);
}
