#include <iostream>
#include <fstream>
using namespace std;

int main()
{
   ifstream fin("fact.in");
   ofstream fout("fact.out");
   int t,P,i=5,k=0;   
   fin>>P;
   if(P==0)
   {
        fout<<1;
        return 0;
   }
   while(k<P)
   {
      t=i;
      while(t%5==0)
      {
          t=t/5;
          k++;
      }   
      i=i+5;
      
   }
   fout<<i-5;
   fin.close();
   fout.close();
   return 0;
}