m = [i for i in range(1, 13)]

d = [i+1 for i in range(9)]
for i in range(10, 32):
    i = str(i)
    d += [int(i[0]) + int(i[1])]

cnt = 0
for i in m:
    for j in d:
        if i == j:
            cnt += 1

print(cnt)