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 Book_Reading {
    public static void main(String[] args) throws java.lang.Exception{
        BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
        int t = Integer.parseInt(input.readLine());
        for(int i=0;i<t;i++){
            String[] nm = input.readLine().split(" ");
            long n = Long.parseLong(nm[0]);
            long m = Long.parseLong(nm[1]);
            long res = 0;
            long a = n/m;
            ArrayList<Long> nums = new ArrayList<Long>();
            nums.add(m%10);
            long j = 2;
            long sum = nums.get(0);
            while(((m*j)%10)!=(m%10)){
                nums.add(((m*j)%10));
                sum = sum+((m*j)%10);
                j++;
            }
            long r = a%nums.size();
            a = a/nums.size();
            res = res + sum*a;
            for(int k=0;k<r;k++){
                res = res+nums.get(k);
            }
            System.out.println(res);
        }
    }
}
