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 chess {
    public static void main(String[] args) {

        Scanner sc1 = new Scanner(System.in);
        long porog = sc1.nextLong();
        for (long i = 0; i < porog; i++) {
            long starnici = sc1.nextLong();
            long delitel = sc1.nextLong();
            long res = 0;
            long temp = 0;
            long proporcia = 0;
            long pr = 0;
            if (delitel < starnici + 1) {
                temp = starnici / delitel;
                if (starnici / delitel >= 10) {
                    for (long c = 1; c < 10; c++) {
                        proporcia = proporcia + ((delitel * c) % 10);
                    }
                    for (long f = 1; f <= (temp % 10); f++) {
                        pr = pr + ((delitel * f) % 10);
                    }
                    res = ((temp / 10) * proporcia) + pr;
                } else {
                    for (long g = 1; g <= temp; g++) {
                        if ((delitel * g) >= 10) {
                            pr = pr + ((delitel * g) % 10);
                        } else {
                            pr = pr + (delitel * g);
                        }

                    }
                    res = pr;
                }
                System.out.println(res);
            } else {
                System.out.println(0);
            }
        }
    }
}