K = int(input())
A = [2,3,5,7,11,13]
B = [4,6,8,9,10,12]
L = []
for i in range(6) :
    for j in range(6) :
        n = A[i]*B[j]
        L.append(n)
C = [12,18,20,24,30]
if K in C :
    print(2/36)
elif K in L :
    print(1/36)
else :
    print(0)