*******************************
*** The hack uses generator ***
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** Command line arguments **
no arguments

** Generated test **
1000
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
20 21
2...

** Generator source **
#include <bits/stdc++.h>
using namespace std;
//SET PRECIOSION   cout << fixed ;  cout << setprecision(n) << ans << endl;
#define ll long long
#define ld long double
#define pair<ll,ll> PAIR
#define endl "\n"
#define mod 1000000007
#define sz(v) ((int)(v).size())
#define all(v) (v).begin(), (v).end()
#define pb push_back
#define N 3000009
#define FAST ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
ll SET(ll n, ll pos) { return n = n | (1 << pos ); }
ll RESET(ll n, ll pos) { return n = n & ~(1<<pos);}
bool CHECK(ll n, ll pos) { return (bool) (n & (1<<pos));}
vector <ll> v;
ll x,y,z,a,b,c,sum,ans,total,t,cnt,n,m,k,p,q,r,l,w,right,left,row,col,kase;
string s1,s2;
map<ll,ll> mp;
set<ll> s;
map<ll,ll> :: iterator itr1, ptr1;
set<ll> :: iterator itr, ptr;
ll arr[N] , arr1[N] , ind[N];
int main()
{
	///Peace be with you.
	FAST;
	cout<<1000<<endl;

	for(ll i=0; i<1000;i++)
        cout<<20<<" "<<21<<endl;

	return 0;
}