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.Scanner;

public class Main {

	public static void main(String args[])
	{
		Scanner scan=new Scanner(System.in);
		int n=scan.nextInt();
		for(int i=0;i<n;i++)
		{
			long x=0L;
			x=scan.nextLong();
			long y=scan.nextLong();
			long times=x/y;
			long haha[]=new long[10];
			long po=0;
//			System.out.println(x +" "+y);
//			System.out.println(1%10);
			for(int j=1;j<=10;j++)
			{
//				System.out.println((j*y)%10);
				haha[j-1]=(j*y)%10;
				po+=haha[j-1];
			}long sum=0;
			for(int j=0;j<times%10;j++)
			{
//				System.out.println(haha[j]+"l;olqop");
				sum+=haha[j];
			}
			sum=sum+(times/10)*po;
			System.out.println(sum);
				
		}
	}
}
