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.HashMap;
import java.util.Scanner;

public class TaskC {
	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		int q = s.nextInt();
		
		while(q-- > 0) {
			long n = s.nextLong();
			long m = s.nextLong();
			
			long lastDig = m%10;
			
			ArrayList list = new ArrayList();
			
			list.add(lastDig);
			//System.out.println(lastDig);
			
			long next = (2*lastDig)%10;
			
			
			while(next != lastDig) {
				list.add(next);
				
				next = (next+lastDig)%10;
			}
			
			long div = n/m;
			//System.out.println(div);
			long occ = div/list.size();
			//System.out.println(occ);
			
			long total = 0;
			
			for(int i=0;i<list.size();i++ ) {
				total += ((long) list.get(i))*occ;
			}
			
			long more = div%list.size();
			
			//System.out.println(list.size());
			
			for(int i=0;i<more;i++) {
				total += (long) list.get(i);
			}
			
			System.out.println(total);
		}
	}
}
