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#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef long long ll;
typedef pair<int,int> PII;
typedef double db;
//mt19937 mrand(random_device{}());
const ll mod=1000000009;
//int rnd(int x) { return mrand() % x;}
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head
 
const int N=5e3+5;
 
#define INF 0x3f3f3f3f
 
template<class T> inline void read(T &x) {
    x=0; int c=getchar(),f=1;
    for (;!isdigit(c);c=getchar()) if (c==45) f=-1;
    for (;isdigit(c);c=getchar()) (x*=10)+=f*(c-'0');
}
int L;
PII e[N];
 
int main() {
	read(L);
	if (L==1) {
		puts("2");
		puts("2 -1");
		puts("-1 -1");
		return 0;
	}
	int p=31-__builtin_clz(L);
	e[3*p+1]=mp(-1,-1);
	rep(i,1,3*p+1)
		if (i%3==1) {
			e[i]=mp(i+1,-1);
			if (L&(1<<i/3)) e[i].se=3*p+1;
		} 
		else if (i%3==2) e[i]=mp(i+1,i+2);
		else e[i]=mp(i+1,-1);
	printf("%d\n",3*p+1);
	rep(i,1,3*p+2) printf("%d %d\n",e[i].fi,e[i].se);
}