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.*;
public class MyClass {
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        int t=sc.nextInt();
        for(int k=0; k<t; k++)
        {
            long n=sc.nextLong();
            long m=sc.nextLong();
            long sum=0;
            if(n>=m)
            {
                long count = n/m;
                if(count>10)
                {
                for(long i=m; i<11*m; i=i+m)
                {
                    sum = sum + i%10;
                }
                sum = sum*(count/10);
                long rem = count%10;
                long start = (count-rem+1)*m;
                for(long i=0; i<rem; i++)
                {
                    sum = sum + start%10;
                    start = start + m;
                }
                
                }
                else
                {
                for(long i=m; i<n+1; i=i+m)
                {
                    sum = sum + i%10;
                }
                }
                System.out.println(sum);
            }
            else
                System.out.println("0");
        }
    }
}