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.io.IOException;
import java.util.Scanner;

public class Codeforces {
	public static void main(String[] args)throws IOException{
		Scanner sc=new Scanner(System.in);
		int q=sc.nextInt();
		while(q-->0) {
			long n=sc.nextLong();
			long m=sc.nextLong();
			long num=n/m;
			//System.out.println(num);
			long sum=0;
			if(num<10) {
				for(long i=1;i<=num;i++) {
					long tmp = (m*i)%10;
					//System.out.println(tmp);
					sum+=tmp;
				}
				System.out.println(sum);
				continue;
			}
			for(long i=1;i<=10;i++) {
				long tmp = (m*i)%10;
				//System.out.println(tmp);
				sum+=tmp;
				//System.out.println(sum);
			}
			//System.out.println(sum+" "+n);
			sum=sum*(num/10);
			num=num%10;
			//System.out.println(sum+" "+n);
			for(long i=1;i<=num;i++) {
				sum+=((m*i)%10);
			}
			System.out.println(sum);
		}
	}
}
