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#include<bits/stdc++.h>
using namespace std;
int main()
{
    ios_base::sync_with_stdio(0);
    int il;
    vector<bool> vec;
    cin >> il;
    while(il>0)
    {
        if(il%2==0)
            vec.push_back(false);
        else
            vec.push_back(true);
        il/=2;
    }
    cout << "70"<<endl;
    for(int k=1;k<=70;k++)
    {
        if(k==69 || k ==70)
            cout << "-1 -1"<<endl;
        else if(k%2==1)
            cout << k+1 << " " << k+2 <<endl;
        else
        {
            if(k/2 - 1 < vec.size() && vec[k/2 - 1])
                cout << "70 "<< k+1 <<endl;
            else
                cout << "-1 "<< k+1 <<endl;
        }
    }
}