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
/**
 * Created by Rukshar Alam on 11/22/2019.
 */
import java.util.Scanner;
public class BookReading_1213C {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int query = sc.nextInt();

        for(int q =0;q<query;q++){
            long n = sc.nextLong(); long m = sc.nextLong();
            n /= m;
            long digits[] = new long[10];

            for(int i =0;i<10;i++){
                digits[i] = ((i+1)*m)%10;
            }
            long sum =0;

            for(int i=0;i<n%10;i++){
             sum+=digits[i];
            }

            long tempSum =0;
            for(int i =0;i<10;i++){
                tempSum+=digits[i];
            }

            sum+= (tempSum*(n/10));

            System.out.println(sum);
        }



    }
}
