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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.util.ArrayList;

public class Main {

    public static void main(String args[]) throws IOException {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        int T = Integer.parseInt(br.readLine());

        for (int t = 0; t < T; t++) {

            String s[] = br.readLine().split(" ");
            long n = Long.parseLong(s[0]);
            long m = Long.parseLong(s[1]);

            ArrayList<Integer> list = new ArrayList<>();
            boolean isVisited[] = new boolean[10];
            long x = m;
            long loop = 0;

            while (true) {
                int k = (int) (x % 10);
                if (isVisited[k] || x > n) {
                    break;
                }
                loop += k;
                list.add(k);
                isVisited[k] = true;
                x += m;
            }

            long ans = 0;

            if (!list.isEmpty()) {
                ans = ((n / m) / list.size()) * loop;
                long r = (n / m) % list.size();
                int index = 0;
                for (long i = 0; i < r; i++) {
                    ans += list.get(index);
                    index++;
                    if (index == list.size()) {
                        index = 0;
                    }
                }
            }

            System.out.println(ans);

        }
    }
}