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

int main()
{
    ifstream in("fact.in");
    in>>p;
    /*n=5;
    q=p;
    q--;
    while(q)
        {
            n=n+5;
            m=n;
            while(m%5==0)
               {
                   q--;
                   m=m/5;
               }
        }*/
    ofstream out("fact.out");
    /*if (p==0)
       out<<1;
    else*/
    if (p==2)
        out<<p*5;
    else
        out<<p*5-5;
    return 0;
}