count=0
for i in range(1,12):
    for j in range(1,31):
        if i==((j//10)+(j-10*(j//10))):
            count+=1
        if i==2 and j==28:
            break
        elif j==30 and (i==4 or i==6 or i==9 or i==11):
            break
print(count)