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 codeforces;
import java.util.*;
/**
 * @author Shivansh Singh
 *
 */
public class Cf1213C {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		long t,n,m,s,i,sum,p,q;
		t=sc.nextLong();
		while(t--!=0) {
			s=sum=0;
			n=sc.nextLong();
			m=sc.nextLong();
			for (i=1;i<=10;i++)
				s+=(m*i)%10;
			p=n/m;
			q=p/10;
			sum+=q*s;
			for (i=1;i<=p-(q*10);i++)
				sum+=(m*i)%10;
			System.out.println(sum);
		}
		sc.close();
	}

}
