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.math.*;
import java.util.*;


public class Main {

   

    
    public static void main(String[] args) throws IOException {
        Scanner in=new Scanner(System.in);
        int t=in.nextInt();
        while(t-->0)
        {
        	long n=in.nextLong();
        	long m=in.nextLong();
        	int a[]=new int[10];
        	long sum=0;
        	for(int i=1;i<10;i++)
        		{
        			a[i]=(int)((m*i)%10);
        			sum+=(long)a[i];
        		}
        	long nbym=n/m;
        	long nbymby10=nbym/10;
        	int nbymMod10=(int)(nbym%10);
        	
        	sum*=nbymby10;
        	for(int i=1;i<=nbymMod10;i++)
        	sum+=(long)a[i];
        	
        	System.out.println(sum);
        	
        }
    }
}
