#描述#
A Benedict monk No. 16 writes down the decimal representations of all natural numbers between and including m and n, m ≤ n. How many 0's will he write down?

#格式#
##输入格式##
Input consists of a sequence of lines. Each line contains two unsigned 32-bit integers m and n, m ≤ n. The last line of input has the value of m negative and this line should not be processed.

##输出格式##
For each line of input print one line of output with one integer number giving the number of 0's written down by the monk.

#样例1#
##样例输入1##

10 11
100 200
0 500
1234567890 2345678901
0 4294967295
-1 -1

##样例输出1##

1
22
92
987654304
3825876150

#限制#
1000ms
32768KB

#提示#

#来源#