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.Scanner;

public class BookReading {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int test = scanner.nextInt();
        scanner.nextLine();

        StringBuilder result = new StringBuilder();
        for (int t = 0; t < test; t++) {
            long n = scanner.nextLong();
            long m = scanner.nextLong();
            scanner.nextLine();

            long digitMod = m % 10;
            if (digitMod == 0) {
                result.append(0 + System.lineSeparator());
                continue;
            }

            long totalNums = n / m;


            int digitChunkCount = 0;
            long chunkTotal = 0;
            if (digitMod == 1 || digitMod == 3 || digitMod == 7 || digitMod == 9) {
                digitChunkCount = 10;
                chunkTotal = 45;
            } else if (digitMod % 2 == 0) {
                digitChunkCount = 5;
                chunkTotal = 20;
            } else if (digitMod == 5) {
                digitChunkCount = 2;
                chunkTotal = 5;
            }

            long chunkCount = totalNums / digitChunkCount;
            long sumFromChunks = chunkCount * chunkTotal;

            long remainingNumCount = totalNums % digitChunkCount;
            long chunkEnd = m * chunkCount * digitChunkCount;
            for (int i = 1; i <= remainingNumCount; i++) {
                long remainingNum = chunkEnd + i * m;
                sumFromChunks += (remainingNum % 10);
            }

            result.append(sumFromChunks);
            result.append(System.lineSeparator());

            // totalnum = 7
            // chunkcount = 1
            // sumfromchunk = 20
            // remaining = 2

            // n = 113
            // m = 16, (16, 32, 48, 64, 80, 96, 112)

            // m = 0 ==> 10, 20..
            // m = 11 ==> 1..10
            // m = 12 ==> 2-4..10
            // m = 13 => 3-6..30
            // m = 14 ==> 4-8..20
            // M = 15 => 5-10
            // m = 16 => 6-30
            // m = 17 => 7-70
            // m = 8 ==> 8-40
            // m = 9 ==> 9-90
        }

        System.out.println(result.toString());

    }
}
