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
/*
        π  
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 */
import java.util.Scanner;
public class CodeForces 
{
    public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        int t = sc.nextInt();
        for(int ii=0;ii<t;ii++)
        {
            long n = sc.nextLong();
            long m = sc.nextLong();
            long sum = 0,intm1 = 0,intm2 = 0;
            long a[] = new long[11];
            for(int i=1;i<=10;i++)
            {
                a[i] = (m*i)%10;
                intm1+=a[i];
            }
            sum+=((n/(m*10))*(intm1));
            for(int i=1;i<=(n/m)%10;i++)
            {
                intm2+=a[i];
            }
            sum+=intm2;
            System.out.println(sum);
        }
    }
}