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.*;
import java.lang.*;

public final class book_reading {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int l = in.nextInt();
        while(l-->0) {
            long n = in.nextLong();
            long m = in.nextLong();
            int t = (int)(m%10);
            int sum = 0;
            for(int i=1;i<10;i++) {
                sum+=(t*i)%10;
            }
            long k = n/m;
            int j = (int)(k%10);
            int e = 0;
            for(int i=1;i<=j;i++) e+=(i*t)%10;
            //System.out.println((k/10)*sum+" "+e);
            long answer = (long)(k/10)*sum + (long)e;
            System.out.println(answer);
        }
    }
}