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 q = scanner.nextInt();
        while (q-- > 0) {
            long n = scanner.nextLong(), m = scanner.nextLong();
            long sum = 0;
            long tensum = 0;
            long []digits = new long[10];
            for (int i=1; i<11; i++) {
                digits[i-1] = (m*i)%10;
                tensum += digits[i-1];
            }
            
            sum = tensum*(n / (m*10));
            for (long i=1*m; i<=(n % (m*10)); i+=m) {
                sum += i%10;
            }
            
            System.out.println(sum);
        }
    }
}
