#include<cstdio>#include<cstring>#include<algorithm>#include<set>#include<iostream>#include<bits/stdc++.h>usingnamespace std;typedeflonglong ll;#define SIS std::ios::sync_with_stdio(false)#define space putchar(' ')#define enter putchar('\n')typedef pair<int,int> PII;constint mod=1e4+7;constint N=2e6+10;constint inf=0x7f7f7f7f;
ll gcd(ll a,ll b){return b==0?a:gcd(b,a%b);}
ll lcm(ll a,ll b){return a*(b/gcd(a,b));}template<classT>voidread(T &x){char c;bool op =0;while(c =getchar(), c <'0'|| c >'9')if(c =='-')
op =1;
x = c -'0';while(c =getchar(), c >='0'&& c <='9')
x = x *10+ c -'0';if(op)
x =-x;}template<classT>voidwrite(T x){if(x <0)
x =-x,putchar('-');if(x >=10)write(x /10);putchar('0'+ x %10);}intmain(){
SIS;int n;read(n);printf("%d\n",(n+1)*3+1);printf("0 0\n");for(int i=0;i<=n;i++){printf("%d %d\n",i+1,i+1);printf("%d %d\n",i+1,i);printf("%d %d\n",i,i+1);}return0;}