def solve():
    K = int(input())
    p = (2, 3, 5, 7, 11, 13)
    q = (4, 6, 8, 9, 10, 12)
    pq = [0] * 201
    for pi in p:
        for qi in q:
            pq[pi * qi] += 1
    return pq[K]/36.0

print(solve())