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 Problem_1213_C {
    private static Scanner scanner = new Scanner(System.in);
    public static void main (String [] args) {

        int q = scanner.nextInt();
        long[] array = new long[q];

        for (int i=0; i < q; i++){
            long digit = 1;
            long sumOfDigit = 0;
            int count = 0;
            long sum = 0;
            long n = scanner.nextLong();
            long m = scanner.nextLong();
            long g = m;

            while (true){
                digit = g % 10;
                if (digit == 0){
                    count++;
                    break;
                }
                g += m;
                count++;
                sumOfDigit += digit;
            }
//            System.out.println("count: " + count);
//            System.out.println("sumOfDigit = " + sumOfDigit);
            long temp = n - (n / (count * m)) * count * m;
//            System.out.println("temp: " + temp);
            sum = (n / (count  * m)) * sumOfDigit;
            if (temp >= m){
                for(long z = m; z <= temp; z += m){
                    digit = z % 10;
                     sum += digit;
                }
            }


            array[i] = sum;
        }


        for (int i=0; i<q; i++){
            System.out.println(array[i]);
        }








//        for (int i=0; i < q; i++){
//            long temp = 0;
//            long sum = 0;
//            long n = scanner.nextLong();
//            long m = scanner.nextLong();
//            for (long j=m; j<=n; j+=m){
//                if (n==1 && m==1){
//                    sum = 1;
//                    break;
//                }
//                    temp = j % 10;
//                    sum += temp;
//
//            }
//            array[i] = sum;
//        }




        scanner.close();
    }
}
