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.*;
import java.math.*;

public class Main {
	static public void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int T = in.nextInt();
		while (T-- > 0) {
			long n = in.nextLong();
			long m = in.nextLong();
			if (m > n) {
				System.out.println(0);
				continue;
			}
			long t = n / m;
			long x = m;
			ArrayList<Long> arr = new ArrayList<>();
			while (x <= n && (arr.size() == 0 || x % 10 != arr.get(0))) {
				arr.add(x % 10);
				x += m;
			}
			Long[] circle = new Long[arr.size()];
			arr.toArray(circle);
			Long ans = 0L;
			for (Long i : circle) {
				ans += i;
			}
			ans *= t / circle.length;
			t %= circle.length;
			for (int i = 0; i < t; ++i) {
				ans += circle[i];
			}
			System.out.println(ans);
		}
	}
}