using namespace std;
#include <fstream>

int main()
{
        unsigned long int p = 0, n = 0;
        ifstream fin("fact.in");
        ofstream fout("fact.out");
        fin >> p;
        n = p * 5 - 5;
        fout << n << "\n";
        fin.close();
        fout.close();
        return 0;
}