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#include <bits/stdc++.h>
#define ll long long
using namespace std;
int k, dod[100];
int main()
{
    cin>>k;
    vector<int> sum;
    int i=29, pot=1<<29;
    while(k){
        if(k>=pot){
            k-=pot;
            sum.push_back(i);
        }
        i--;
        pot/=2;
    }
//   for(int j: sum) cout<<j<<' ';
//   cout<<endl;
   int n=2*sum[0]+2;
   cout<<n<<'\n';
   for(int j=1; j<sum.size(); ++j){
    dod[2*sum[j]+2]=n;
   }
   for(int i=1; i<n; ++i){
    cout<<i+1<<' ';
    if(i%2==1&&i+2<=n) cout<<i+2<<'\n';
    else if(i%2==0&&dod[i])cout<<dod[i]<<'\n';
    else cout<<-1<<'\n';
   }
   cout<<-1<<' '<<-1;
    return 0;
}