#coding:utf-8

cal={1:range(1,32),2:range(1,29),3:range(1,32),4:range(31),5:range(1,32),6:range(1,31),\
7:range(1,32),8:range(1,32),9:range(1,31),10:range(1,32),11:range(1,31),12:range(1,32)}

cnt=0
for i in range(1,13):
	for u in cal[i]:
		if i == (u // 10) + (u % 10):
			cnt+=1

print cnt