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
//package Div3;

import java.io.*;
import java.util.StringTokenizer;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.HashMap;
import java.util.TreeSet;
import java.util.TreeMap;
import java.util.Arrays;
import java.util.Collections;

public class Submission {
	public static void main(String[] args) throws IOException, InterruptedException {
		Scanner sc = new Scanner(System.in);
		PrintWriter pw = new PrintWriter(System.out);
		int q = sc.nextInt();
		while (q-- > 0) {
			long n = sc.nextLong();
			long m = sc.nextLong();
			HashSet<Integer> set = new HashSet<>();
			HashMap<Integer, Integer> map = new HashMap<>();
			for (long i = 1;; i++) {
				long val = ((m * i) % 10);
				long actualVal = (m * i);
				if (set.contains((int) val) || actualVal > n)
					break;
				else {
					set.add((int) val);
					map.put((int) i, (int) val);
				}
			}
			long times = n / m;
			long iterationsRemoved = 0;
			long forEach = 1;
			if (set.size() != 0) {
				forEach = times / set.size();
				iterationsRemoved = times % set.size();
			}
			long ans = 0;
			for (int i = 1; i <= map.size() && forEach >= 1; i++) {
				long num = map.getOrDefault(i, 0);
				ans += num * forEach;
			}
			if (iterationsRemoved != 0)
				for (int i = 1; i <= iterationsRemoved; i++) {
					long num = map.get(i);
					ans += num;
				}

			System.out.println(ans);
		}
	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream system) {
			br = new BufferedReader(new InputStreamReader(system));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

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

		public char nextChar() throws IOException {
			return next().charAt(0);
		}

		public Long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

		public void waitForInput() throws InterruptedException {
			Thread.sleep(4000);
		}
	}
}
