#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define F first
#define S second
#define endl '\n'
#define all(v) v.begin() , v.end()
#define int long long
int const M = 1e6 , mod = 1e9 + 7 , N = 5e4 + 25;
ll T , n , d , x , y , In[M] , Out[M];
pair<ll , ll>p[M];
main() {
ios_base::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
cin >> n;
for(int i = 1 ; i <= n ; ++i) cin >> p[i].F >> p[i].S;
sort(p + 1 , p + n + 1);
ll x = 0 , y = 0;
cout << 2 * n << endl;
for(int i = 1 ; i <= n ; ++i) {
cout << p[i].F << " " << y << endl;
cout << p[i].F << " " << p[i].S << endl;
x = p[i].F;
y = p[i].S;
}
return 0;
}
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define F first
#define S second
#define endl '\n'
#define all(v) v.begin() , v.end()
#define int long long
int const M = 1e6 , mod = 1e9 + 7 , N = 5e4 + 25;
ll T , n , d , x , y , In[M] , Out[M];
pair<ll , ll>p[M];
main() {
ios_base::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
cin >> n;
for(int i = 1 ; i <= n ; ++i) cin >> p[i].F >> p[i].S;
sort(p + 1 , p + n + 1);
ll x = 0 , y = 0;
cout << 2 * n << endl;
for(int i = 1 ; i <= n ; ++i) {
cout << p[i].F << " " << y << endl;
cout << p[i].F << " " << p[i].S << endl;
x = p[i].F;
y = p[i].S;
}
return 0;
}
