#include <fstream>

using namespace std;

ifstream fin("fact.in");
ofstream gout("fact.out");

int main()
{
    int n, num = 1;
    fin >> n;
    if (n)
        {num = 0;
        while (n)
        {
            if (n>5)
            {
                n-=6;
                num += 25;
            }
            else
            {
                num += n*5;
                n=0;
            }
        }
        }
    gout << num;
    return 0;
}