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# Problem MHow many 0's?

A Benedict monk No. 16 writes down the decimal representations of all natural numbers between and including $m$ and $n$, $m \le n$. How many $0$’s will he write down?

## Input

Input consists of a sequence of lines. Each line contains two unsigned 32-bit integers $m$ and $n$, $m \le n$. The last line of input has the value of $m$ negative and this line should not be processed. There are at most $15\, 000$ test cases.

## Output

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.

Sample Input 1 Sample Output 1
10 11
100 200
0 500
1234567890 2345678901
0 4294967295
-1 -1

1
22
92
987654304
3825876150