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 lastDig
{
    public static void main(String args[])
    {
        Scanner sc=new Scanner (System.in);
        //System.out.println("44");
        int t =sc.nextInt();
        while(t-->0)
        {
            long n =sc.nextLong();
            long m =sc.nextLong();
            long seq = n/m;
            long lastDig = m%10;
            long arr[]=new long [10];
            arr[0]=lastDig;long sum=arr[0];
            for(int i=1;i<10;i++)
             {
                 arr[i]=(arr[i-1]+lastDig)%10;
                 sum+=arr[i];
                }
               
            //System.out.println(sum);
            long times = seq/10;
            long ans = times*sum;
            long left = seq%10;
            for(int i = 0;i<left;i++)
             ans+=arr[i];
             
             System.out.println(ans);
            }
        }
    }