How 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 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.

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 |