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
/*package whatever //do not write package name here */

import java.util.*;
import java.lang.*;
import java.io.*;

public class GFG {
	public static void main (String[] args) {
	Scanner sc=new Scanner(System.in);
	int a=sc.nextInt();
	for(int i=0;i<a;i++){
	long b=sc.nextLong();
	long c=sc.nextLong();
	long sum=0;
	long sum1=0;
	long[]arr=new long[10];
	for(int j=0;j<10;j++)
	{arr[j]=(c*j)%10;
	sum=sum+arr[j];}
	long h=10;
	sum1=((b/c)/h)*sum;
long y=(b/c)%h;
	for(int j=1;j<=y;j++)
	sum1=sum1+arr[j];
	
	System.out.println(sum1);
	}
	
	}
}