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.*;
import java.io.*;

public class BookReading {

    public static void main(String[] args)throws Exception{
        FastReader in=new FastReader();
        PrintWriter out = new PrintWriter(System.out);
        int tc = in.nextInt();
        for (int t = 0; t < tc; t++) {
            long n = in.nextLong(), m = in.nextLong();
            List<Integer> al = new ArrayList<>();
            long x=m;
            while(!al.contains((int)(x%10))){
                al.add((int)(x%10));
                x+=m;
            }
            long a=n/m;
            long b=a/al.size();
            long rem=a%al.size();
            long ans=0;
            for (int i = 0; i < al.size(); i++) {
                if(rem>0){
                    rem--;
                    ans+=(al.get(i)*(b+1));
                }else{
                    ans+=(al.get(i)*(b));
                }
            }//for
            out.println(ans);
        }//fortc
        out.flush();
    }//psvm
    static class FastReader {

        BufferedReader br;
        StringTokenizer st;

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

        FastReader(File f) {
            try {
                br = new BufferedReader(new FileReader(f));
            } catch (FileNotFoundException x) {
                System.out.println(x);
            }
        }

        String next() throws IOException {
            while (st == null || !st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
            return st.nextToken();
        }

        String nextLine() throws IOException {
            return br.readLine();
        }

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

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

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

        boolean hasNext() throws IOException {
            String s = br.readLine();
            if (s == null) {
                return false;
            }
            st = new StringTokenizer(s);
            return true;
        }
    }
}//class
