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.IOException;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;
import java.util.StringTokenizer;

public class Main {

    public static void main(String[] args){

        FastReader fastReader = new FastReader();

        long t = fastReader.nextLong();

        while (t-- >0){

            long n = fastReader.nextLong();
            long m = fastReader.nextLong();

            long sum = 0;

            for(long i=m ; i<= (m*10) ; i+=m){

                sum += (i%10);

            }

//            System.out.println("Sum incremented: " + sum);

            long poorePoore = n / (m*10);

            sum = (sum * poorePoore);

//            System.out.println("Sum now: " + sum);

            long remainingPages = n % (m*10);

            long pageToStart = (poorePoore * m* 10) + m;

//            System.out.println("Page to start :" + pageToStart);

            for(long pageNumber = pageToStart ; pageNumber<=n ; pageNumber+= m){

                sum += pageNumber % 10;

            }

//            System.out.println("Sum at end: " + sum);


            System.out.println(sum);



        }








    }

































































































            static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader()
        {
            br = new BufferedReader(
                    new InputStreamReader(System.in));
        }

        String next()
        {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt() { return Integer.parseInt(next()); }

        long nextLong() { return Long.parseLong(next()); }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine()
        {
            String str = "";
            try {
                str = br.readLine();
            }
            catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }



    }

