#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    vector<pair<int,int>> a(3), ans, S;
    for(auto &&[y, x] : a) cin >> y >> x;
    sort(a.begin(), a.end());
    do{
        auto [y0, x0] = a[0];
        auto [y1, x1] = a[1];
        auto [y2, x2] = a[2];
        if(y0 + x0 == y1 + x1 && y0 + x0 == y2 + x2){
            cout << "-1\n";
            return 0;
        }
        if(y0 + x0 == y1 + x1 && y0 - x0 == y2 - x2){
            cout << "-1\n";
            return 0;
        }
        if(y0 - x0 == y1 - x1 && y0 - x0 == y2 - x2){
            cout << "-1\n";
            return 0;
        }
    }while(next_permutation(a.begin(), a.end()));
    do{
        auto [y0, x0] = a[0];
        auto [y1, x1] = a[1];
        auto [y2, x2] = a[2];
        int u0 = y0 + x0, v0 = y0 - x0;
        int u1 = y1 + x1, v1 = y1 - x1;
        int u2 = y2 + x2, v2 = y2 - x2;
        int U = u0 + u1, V = v0 + v1;
        S.emplace_back((U + V) / 2, (U - V) / 2);
        U = u0 + u1, V = v0 + v2;
        S.emplace_back((U + V) / 2, (U - V) / 2);
        U = u0 + u2, V = v0 + v1;
        S.emplace_back((U + V) / 2, (U - V) / 2);
        U = u0 - u1, V = v0 + v1;
        S.emplace_back((U + V) / 2, (U - V) / 2);
        U = u0 + u1, V = v0 - v1;
        S.emplace_back((U + V) / 2, (U - V) / 2);
        U = u0 - u1, V = v0 + v2;
        S.emplace_back((U + V) / 2, (U - V) / 2);
        U = u0 + u1, V = v0 - v2;
        S.emplace_back((U + V) / 2, (U - V) / 2);
        U = u0 - u2, V = v0 + v1;
        S.emplace_back((U + V) / 2, (U - V) / 2);
    }while(next_permutation(a.begin(), a.end()));
    auto f = [&](int y, int x, int p){
        auto [y0, x0] = a[p];
        return abs(y - y0) + abs(x - x0);
    };
    for(auto [y, x] : S){
        if(f(y, x, 0) == f(y, x, 1) && f(y, x, 1) == f(y, x, 2)){
            ans.emplace_back(y, x);
        }
        swap(y, x);
        if(f(y, x, 0) == f(y, x, 1) && f(y, x, 1) == f(y, x, 2)){
            ans.emplace_back(y, x);
        }
    }
    sort(ans.begin(), ans.end());
    ans.erase(unique(ans.begin(), ans.end()), ans.end());
    cout << ans.size() << '\n';
    for(auto [y, x] : ans) cout << y << ' ' << x << '\n';
}