Polycarp is reading a book consisting of n pages numbered from 1 to n. Every time he finishes the page with the number divisible by m, he writes down the last digit of this page number. For example, if n=15 and m=5, pages divisible by m are 5, 10, 15. Their last digits are 5, 0, 5 correspondingly, their sum is 10.

Your task is to calculate the sum of all digits Polycarp has written down.

You have to answer q independent queries.

Input

The first line of the input contains one integer q (1 ≤ q ≤ 1000) — the number of queries.

The following q lines contain queries, one per line. Each query is given as two integers n and m (1 ≤ n, m ≤ 10^{16}) — the number of pages in the book and required divisor, respectively.

Output

For each query print the answer for it — the sum of digits written down by Polycarp.

Example

Input


7
1 1
10 1
100 3
1024 14
998244353 1337
123 144
1234312817382646 13


Output


1
45
153
294
3359835
0
427262129093995

import java.util.Scanner;

public class BookReading {

    public static void main(String args[]) {
        Scanner scan = new Scanner(System.in);
        int t = scan.nextInt();
        while (t-- > 0) {
            long n = scan.nextLong();
            long m = scan.nextLong();
            long k = 0;
            for (long i = 1; i <= 10; i++) {
                String s = String.valueOf(m * i);
                k += s.charAt(s.length() - 1) - '0';
            }

            long temp = n / (m * 10);
            long res = k * temp;
            long p = 0;
            for (long i = temp * (m * 10); i <= n; i += m) {
                String s = String.valueOf(i);
                p += s.charAt(s.length() - 1) - '0';

            }
            System.out.println(res + p);
        }
    }

}
