c = 0
n = int(input("Введите N: "))/2
r = int(10**n)
for i in range (0, r ):
    l_i = list(str(i))
    sum_i = 0
    for el in l_i:
        sum_i += int(el)

    for k in range (0, r):
            l_k = list(str(k))
            sum_k = 0
            for el in l_k:
                sum_k += int(el)

            if sum_i == sum_k - 1 or sum_i == sum_k + 1:
                    #print(f"Билет {i} | {k}") #вывод билета, который подошел
                    c +=1


print(c)