题解 | #[NOIP2010]数字统计#
[NOIP2010]数字统计
http://www.nowcoder.com/practice/179d9754eeaf48a1b9a49dc1d438525a
l,r=list(map(int,input().split()))
def count_two(a,b):
cnt=0
for x in range(l,r+1):
x=str(x)
cnt+=x.count('2')
return cnt
print(count_two(l,r))
