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.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int q = sc.nextInt();
		for (int tc = 0; tc < q; tc++) {
			long n = sc.nextLong();
			long m = sc.nextLong();

			System.out.println(solve(n, m));
		}

		sc.close();
	}

	static long solve(long n, long m) {
		List<Integer> cycle = findCycle((int) (m % 10));

		return n / m / cycle.size() * cycle.stream().mapToInt(x -> x).sum()
				+ cycle.stream().limit(n / m % cycle.size()).mapToInt(x -> x).sum();
	}

	static List<Integer> findCycle(int step) {
		int digit = 0;
		List<Integer> result = new ArrayList<>();
		while (true) {
			digit = (digit + step) % 10;
			result.add(digit);

			if (digit == 0) {
				return result;
			}
		}
	}
}
