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 ProblemC {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		Scanner s = new Scanner(System.in);
		
		int q = s.nextInt();
		int[] arr = new int[10];
		
		arr[2] = arr[4] = arr[6] = arr[8] = 5;
		arr[3] = arr[9] = arr[7] = 10;
		arr[1] = 10;
		arr[5] = 2;
		arr[0] = 1;
		int[] sum = new int[10];
		
		sum[2] = sum[4] = sum[6] = sum[8] = 20;
		sum[3] = sum[9] =  sum[7] = 45;
		sum[1] = 45;
		sum[5] = 5;
		sum[0] = 0;
		for(int z = 0;z<q;z++)
		{
			long n = s.nextLong();
			long m = s.nextLong();
			
			int digit = (int)(m%10);
			
			if(digit==0)
			{
				System.out.println(0);
				continue;
			}
			long div = n/m;
			long gp = div/arr[digit];
			long rem = div%arr[digit];
			long ans = gp*sum[digit] + remaining(rem, digit);
			
			System.out.println(ans);
			
			
		}
		
		
	}
	
	public static long remaining(long rem, int digit)
	{
		long ans = 0;
		for(int i=1;i<=rem;i++)
		{
			ans += (digit*i)%10;
		}
		
		return ans;
	}


}
