#include <fstream>
using namespace std;
int main()
{
    ifstream f("fact.in");
    ofstream g("fact.out");
    int pr,i,k,p;
    f>>p;
    if(p==0)
    {
        k=p*5+1;
    }
    else
    {
        k=p*5;
        for(i=5;i<=100;i+=5)
        {
            if(k>=5*i&&p<<25*i)
                k=k-5;
        }
    }
    g<<k;
}