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.*;
public class BookReading {

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		Scanner sc = new Scanner(System.in);
		int q = sc.nextInt();
		
		while(q-->0)
		{
			long n = sc.nextLong();
			long m = sc.nextLong();
			long ans=0;
			long arr[] = new long[11];
			
			for(int i=1;i<=10;++i)
			{
				arr[i] = arr[i-1]+((i * m)%10);
			}
			
			  long div = (n/m);
			  int a = (int)(div%10);
			  if(a!=0)
				  ans = (arr[10] * ((div-a)/10))+(arr[a]);
			  else
				  ans = (arr[10]*div/10);
			  System.out.println(ans);
			 
		}
	}

}
