#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

ifstream fin("armonica.in");
ofstream fout("armonica.out");
vector <pair<long long, long long>>v;
long long x, a, b,i,j;
int main()
{
   fin>>b;
   for(long long i=1;i<b;i++)
   {
       if((2*i-b)!=0){
       x=(i*b)/(2*i-b);
        if(x>0)
       if((2*i*x)%(i+x)==0)
       v.push_back(make_pair(i,x));//cout<<i<<" "<<x<<endl;
   }}
   fout<<v.size()*2+1<<"\n";
   fout<<b<<" "<<b<<'\n';
   for(int i=0;i<v.size();i++)
   {
       fout<<v[i].first<<" "<<v[i].second<<'\n';
       fout<<v[i].second<<" "<<v[i].first<<'\n';
   }
    return 0;
}