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#include<iostream>

using namespace std;

int main()
{
    cin.tie(0);
    cout.tie(0);
    ios_base::sync_with_stdio(0);
    long long k,pot=1,ile=0,dodatkowo;
    cin>>k;
    while(pot<=k)
    {
        pot*=2;
        ile++;
    }
    pot/=2;
    ile--;
    cout<<ile*2+2<<"\n";
    dodatkowo=k-pot;
    for(int i=1;i<ile*2+1;i+=2)
    {
        cout<<i+1<<" "<<i+2<<"\n";
        if(dodatkowo%2==1)
        {
            cout<<i+2<<" "<<ile*2+2<<"\n";
            dodatkowo--;
        }
        else cout<<i+2<<" -1\n";
        dodatkowo/=2;
    }
    cout<<ile*2+2<<" -1\n";
    cout<<"-1 -1\n";
    return 0;
}