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.awt.Point;
import java.util.*;
import java.io.*;
import java.lang.*;

public class Solution
{
    public static void main(String[] args) throws java.lang.Exception
    {
        Scanner s=new Scanner(System.in);
        int t=s.nextInt();
        while(t-->0){
            long n = s.nextLong();
            long m = s.nextLong();
            long x = n/m;
            long[] arr;
            long ans = 0l;
            //odd --> 10=x*10;
            if(m%2!=0){
                arr=new long[11];
                long y=0l;
                for(int i=1;i<=10;i++){
                    y=(m*i);
                    arr[i]=arr[i-1]+(y%10);
                    //System.out.println(arr[i]+","+y);
                }
                ans=((x/10)*arr[10])+arr[(int)(x%10)];
            }
            //even --> 10=x*5;
            else{
                arr=new long[6]; 
                long y=0l;
                for(int i=1;i<=5;i++){
                    y=(m*i);
                    arr[i]=arr[i-1]+(y%10);
                    //System.out.print(arr[i]+" ");
                }
                ans=((x/5)*arr[5])+arr[(int)(x%5)];
            }
            
            System.out.println(ans);
            
        }
    }
    
}