import math
cnt = 0
for month in range(1,12+1):
    if month ==4 or month == 6 or month ==9 or month == 11:
        daymax = 30
    elif month == 2:
        daymax = 28
    else:
        daymax = 31
    for day in range(1,daymax+1):
        if month == math.floor(day/10) + day%10:
            cnt=cnt+1
print(cnt)