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.*;
import java.util.*;

public class BankRobbery
{
	public static void main(String[] args) throws IOException
	{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());

		int n = Integer.parseInt(st.nextToken());
		for(int i=0; i<n; i++)
		{
                  ArrayList<Long> repeatingnum = new ArrayList<Long>();
                  st = new StringTokenizer(br.readLine());
                  long numofpg = Long.parseLong(st.nextToken());
                  long divisor = Long.parseLong(st.nextToken());
                  
                  long totalrepeating = 0, total=0;
                  for(long j=0; j<=numofpg; j+=divisor)
                  {
                        if(repeatingnum.contains(j % 10) && j % divisor == 0)
                              break;
                        repeatingnum.add(j % 10);
                        totalrepeating += j % 10;
                  } 
                  total = numofpg / divisor / repeatingnum.size() * totalrepeating;
                  long t =  numofpg / divisor % repeatingnum.size();
                  for(long j=0; j<t+1; j++)
                        total += repeatingnum.get((int)j);
                  
                  System.out.println(total);
		}
	}
}