#include <fstream>
#include <cstdio>

using namespace std;
ifstream fin("fact.in");
ofstream fout("fact.out");
int p, n;
int main()
{
    fin >> p;
    if(p != 0 && p != 5)
        n = ((p / 6) * 25 + (p % 6) * 5);
    else
    {
        if(p == 0)
            n = 1;
        if(p == 5)
            n = -1;
    }
    fout << n << '\n';
    return 0;
}