days = [0,31,28,31,30,31,30,31,31,30,31,30,31]

ans = 0
for i in range(1,13):
    for j in range(1,days[i]+1):
        if 1 <= j <= 9:
            j = "0" + str(j)
        else:
            j = str(j)

        if i == int(j[0]) + int(j[1]):
            ans += 1
            
print(ans)