#include <bits/stdc++.h>
using namespace std;

int main(){
    long long x;cin>>x;
    if(x==1){
        cout<<"2\n1 2\nb g\n";
        return 0;
    }
    vector<int> vc;
    for(int i=3;i<2e5;i++){
        if(x==1||x==2)break;
        while(x%i==0){
            vc.push_back(i);
            x/=i;
        }
    }
    if(x==2)vc.push_back(2);
    if(x>2){
        cout<<"-1\n";
        return 0;
    }
    int sm=0;
    for(auto i:vc)sm+=i+1;
    if(sm>2e15){
        cout<<"-1\n";
        return 0;
    }
    int n=vc.size();
    cout<<sm<<"\n";
    for(int i=1;i<n;i++)cout<<i<<" "<<i+1<<"\n";
    int cnt=n+1;
    for(int i=0;i<n;i++){
        for(int j=0;j<vc[i];j++){
            cout<<i+1<<" "<<cnt<<"\n";
        }
        cnt++;
    }
    for(int i=0;i<sm;i++)cout<<(i<n?"b":"g")<<" \n"[i+1==sm];
}