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.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.PrintStream;
import java.util.Scanner;

public class Main implements Runnable, AutoCloseable {
    Scanner in = new Scanner(new BufferedInputStream(System.in));
    //    StreamTokenizer in = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
    PrintStream out = new PrintStream(new BufferedOutputStream(System.out));

    @Override
    public void run() {
        int t = in.nextInt();
        for (int i = 0; i < t; i++) {
            doOnce();
        }
    }

    private void doOnce() {
        long n = in.nextLong();
        long m = in.nextLong();
        int[] a = new int[10];
        long sum = 0;
        for (int i = 0; i < 10; i++) {
            a[i] = (int) ((m * i) % 10);
            sum += a[i];
        }
        long res = n / (m * 10) * sum;
        int seg = (int) (n % (m * 10) / m);
        for (int i = 1; i <= seg; i++) {
            res += a[i];
        }
        out.println(res);
    }


    public static void main(String[] args) {
        try (Main main = new Main()) {
            main.run();
        }
    }

    @Override
    public void close() {
        out.close();
    }
}