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

ifstream fin("fact.in");
ofstream fout("fact.out");

int p, ap=1, res=5;

int main()
{
    fin>>p;
    if(p==0)
    {
        fout<<"1\n";
        return 0;
    }
    while(ap<p)
    {
        res=res+5;
        int copie=res;
        while(copie%5==0)
        {
            ap++;
            copie=copie/5;
        }
    }
    fout<<res<<'\n';
    return 0;
}