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
/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
public class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		Scanner sc = new Scanner(System.in);
		int t = sc.nextInt();
		while(t-->0){
			long n = sc.nextLong(), m = sc.nextLong();
			List<Long> digits = new ArrayList(); 
			for(long i=m; i<=(n>=10? m*10 : n); i+=m){
				digits.add(i%10);
			}
			long quotient = (long)n/m, sumOfDigits = 0;
			for(Long digit: digits){
				sumOfDigits += digit*(long)(quotient/10);
			}
			int remainder = (int)(quotient%10);
			while(--remainder>=0){
				sumOfDigits += digits.get(remainder); 
			}
			System.out.println(sumOfDigits);
		}
	}
}