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 Reading {

	public static void main(String [] args){
		
		Scanner in = new Scanner(System.in);
		
		int q = in.nextInt();
		
		for (int i = 0; i < q; i++){
			
			long n = in.nextLong();
			long m = in.nextLong();
			
			long steps = 0;
			long sum = 0;
			long num = m;
			
			while(num % 10 != m % 10 || num == m){
				sum += num % 10;
				num += m;
				steps++;
			}
			
			long result = n / (steps * m) * sum;
			
			for (long j = n / (steps * m) * (steps * m); j <= n; j += m)
				result += j % 10;
			
			System.out.println(result);
			
		}
		in.close();
		
	}

}