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 Cost {
	public static void main (String[] args){
		Scanner sc = new Scanner (System.in);
		int l = sc.nextInt();
		for(int i=0;i < l;i++){
			long n = sc.nextLong(), d = sc.nextLong(),r = 0;
			if(n / d < 0 )
				System.out.println(0);
			else if (n ==  d)
				System.out.println(d%10);
			else if(d % 10 == 0)
				System.out.println(0);
			else if(d % 5 == 0){
				long tmp = (long) n / (d * 10);
				r = tmp * 25;
				for(long j = tmp*(d*10)+d;j <= n; j+=d)
					r += (j%10);
				System.out.println(r);
			}
			else if(d % 2 == 0 ){
				long tmp = (long) n / (d * 10);
				r = tmp * 40;
				for(long j = tmp*(d*10)+d;j <= n; j+=d)
					r += (j%10);
				System.out.println(r);
			}
			else{
				long tmp = (long) n / (d * 10);
				r = tmp * 45;
				for(long j = tmp*(d*10)+d;j <= n; j+=d)
					r += (j%10);
				System.out.println(r);
			}
		}
	}
}