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 Main {

    static StringBuilder data = new StringBuilder();
    final static FastReader in = new FastReader();


    public static void main(String[] args) {
        int q = in.nextInt(),f; long n, m,g,s;
        //  int a[]
long [] a;

        long answ;
        for (int i = 0; i < q; i++) {
            n = in.nextLong();
            m = in.nextLong();
            answ = 0;
            a= new long[10];
            g=m;
            s=0;
            f=0;
            if (m > n) {
                data.append(0).append('\n');
            } else {
                for (int j = 0; j < 10; j++) {
                   a[j]=(g%10);
                   g+=m;
                   s+=a[j];
                }

                    answ += (((n / m)/10) * s) ;
              //  System.out.println(((n / m)%10)+" ============= "+s);

                    while (f<((n / m)%10)){
                        answ+=a[f];
                        f++;
                    }




                data.append(answ).append('\n');
            }
        }
        System.out.println(data);

    }


    static void fileOut(String s) {
        File out = new File("output.txt");
        try {
            FileWriter fw = new FileWriter(out);
            fw.write(s);
            fw.flush();
            fw.close();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

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

        public FastReader(String path) {
            try {
                br = new BufferedReader(new
                        InputStreamReader(new FileInputStream(path)));
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
        }

        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());
        }

        float nextFloat() {
            return Float.parseFloat(next());
        }

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


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

}