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#include<bits/stdc++.h>
#define fi first
#define se second
using namespace std;
int n=1;
vector<pair<int,int>> ans;
void f(int k)
{
	if(k==1)
		ans.push_back({-1,-1});
	else if(k%2==1)
	{
		ans.push_back({n+1,-2});
		n++;
		f(k-1);
	}
	else
	{
		ans.push_back({n+1,n+2});
		ans.push_back({n+2,-1});
		n+=2;
		f(k/2);
	}
	return;
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	int k;
	cin>>k;
	if(k==1)
	{
		cout<<"2\n"<<"2 -1\n"<<"-1 -1\n";
		return 0;
	}
	f(k);
	cout<<n<<"\n";
	for(auto v:ans)
	{
		cout<<(v.fi==-2 ? n:v.fi)<<" "<<(v.se==-2 ? n:v.se)<<"\n";
	}
	return 0;
}