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.io.*;
import java.util.Scanner;
/*
7
1 1
10 1
100 3
1024 14
998244353 1337
123 144
1234312817382646 13
 */
public class One {
    public static void main(String args[])throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        Scanner sc = new Scanner(System.in);
        int t = sc.nextInt();
        String s;
        while(t-->0){
            long n = sc.nextLong();
            long b = sc.nextLong();
            long res = 0;
            if(b>n) {
                System.out.println(res);
                continue;
            }
            if(n/b < 10){
                long a = b;
                while(a<=n){
                    res+= a%10;
                    a+=b;
                }
                System.out.println(res);
                continue;
            }
            long a = b;
            long y =0;

            for(int i=1;i<=10;i++){
                res+= a%10;
                a+=b;
                if(i==(n/b)%10){
                    y = res;
                }
            }
            res *= (n / b / 10);
            res += y;
            System.out.println(res);


        }

    }
}
