#include <bits/stdc++.h>
using namespace std;
long long a, b, c, d, i, e, f, g, n, k, l, x[20], y[20], ans;
map<int, int> m;
int main() {
  for (i = 1; i <= 3; i++) {
    cin >> x[i] >> y[i];
    m[x[i]] = y[i];
  }
  sort(x + 1, x + 4);
  sort(y + 1, y + 4);
  ans = x[3] - x[1] + 1 + y[3] - y[1] + 1 - 1;
  cout << ans << endl;
  for (long long i = x[1]; i < x[2]; i++) cout << i << " " << m[x[1]] << endl;
  for (long long i = x[2] + 1; i <= x[3]; i++)
    cout << i << " " << m[x[3]] << endl;
  for (long long i = y[1]; i <= y[3]; i++) cout << x[2] << " " << i << endl;
}
