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.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

public class KCPC2019 {
static long printDivisors(long n, long j) 
    { 
        long Sum = 0;
        long digit = 0;
        int count = 0;
        long b = 0;
        String s = "";
        for (long i=j;i<=n;i+=j) 
        {
           
                digit = i;
                
                s += digit;
                char c = s.charAt(s.length()-1);
                Sum+= Character.getNumericValue(s.charAt(s.length()-1));
                s = "";
                count ++;
                if (c == '0')
                {
                    b =  i;
                    break;
                }
              
                        }
        if (b!=0)
        {
          long cd = n / b;
                Sum *= cd;
        
                b = n % b;
                for (long i = j; i <= b; i+=j) {
                  digit = i;
                
                s += digit;
                char c = s.charAt(s.length()-1);
                Sum+= Character.getNumericValue(s.charAt(s.length()-1));
                s = "";
            
        }
        }   
                return Sum;
    }
    public static void main(String[] args) throws FileNotFoundException 
    {
        Scanner in = new Scanner (System.in);
        
        int T = in.nextInt();
        for (int i = 0; i < T; i++) {
            long n = in.nextLong();
            long j = in.nextLong();
            long sun = printDivisors(n,j);
            System.out.println(sun);
        }
    }
}
