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.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.Scanner;
import java.util.Set;
import java.util.TreeMap;
import java.util.TreeSet;

import sun.security.jgss.TokenTracker;
 
public class MyCode
{
	public static void main(String args[])
	{
	
	   Scanner sc = new Scanner(System.in);
	   int test;
	   long n,m;
	   test = sc.nextInt();
	   while(test>0 && sc.hasNextLong())
	   {
		  test--;
		  n = sc.nextLong();
		  m = sc.nextLong();
		  long div = n/m;
		  long lastElement =  Math.min(10, div);
		  long sum1 = result(m,lastElement);
		  if(div>10)
		  {
			  div = div-10;
			  long iter = div/10;
			  sum1 = sum1+(sum1*iter);
			  iter = div%10;
			  for(int i=1;i<=iter;i++)
			  {
				  long z = (m*i)%10;
				  sum1 = sum1+z;
			  }
		  }
			  
		  System.out.println(sum1);
	   }
	   
	   
	}
	
	public static int result(long number,long lastElement)
	{
		int total=0;
		for(int i=1;i<=lastElement;i++)
		{
			long z = number*i;
			total+= z%10;
		}
		return total;
	}
 
}