#include <iostream>
#include <fstream>
using namespace std;
long long p,l,k,i;
int main()
{
    ifstream f("fact.in");
    ofstream g("fact.out");
    f >> p;
    k=5;
    l=1;
    if (p==0) cout << 1;
    else
    if (p==1) cout << 5;
    else
    for (int i=2;i<=9999999;++i)
    {
        l=l+1;
        if (p==k)
        {
            cout << -1;
            return 0;
        }
        if (i>k)
        {
            l=l-1;
            k=k+6;
        }
        if (i==p)
        {
            l=l*5;
            return 0;
        }
    }
    g << l;
    return 0;
}