n = int(input())
inc = 1
f = 1
ans = []
for y in range(n * 2 + 3):
if y == 0:
ans += [(x, y) for x in range(3)]
elif y == n * 2 + 2:
ans += [(x, y) for x in range(0, 3 * -inc, -inc)]
else:
if f == 0:
ans += [(x, y) for x in range(-2, 3)]
else:
ans += [(0, y), (2 * f, y)]
if f % 2:
inc = -inc
f += inc
print(len(ans))
for i in ans:
print(*i)
#include<bits/stdc++.h>
using namespace std;
#define int long long int
#define endl '\n'
void solve(){
int n;
cin>>n;
cout<<3*n+4<<endl;
int ind;
for(int i=0;i<n+1;i++){
cout<<i<<" "<<i<<endl;
cout<<i+1<<" "<<i<<endl;
cout<<i<<" "<<i+1<<endl;
ind=i;
}
cout<<ind+1<<" "<<ind+1<<endl;
}
int32_t main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
//int t;cin>>t;while(t--)
solve();
return 0;
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