K = int(input())

prime = [2,3,5,7,11,13]
composite = [4,6,8,9,10,12]
product = {}

for p in prime:
    for c in composite:
        if p*c in product:
            product[p*c] += 1
        else:
            product[p*c] = 1
        
if K in product:
    print(product[K] / sum(product.values()))
else:
    print(0)