#include<fstream>
using namespace std;
int n,p,m;

int main()
{
    ifstream in("fact.in");
    in>>p;
    n=5;
    p--;
    while(p)
        {
            n=n+5;
            m=n;
            while(m%5==0)
               {
                   p--;
                   m=m/5;
               }
        }
    ofstream out("fact.out");
    out<<n;
    return 0;
}