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.io.PrintWriter;
import java.util.*;
public class BookReading {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
        int t = in.nextInt();
        for (int i = 0; i < t; i++) {
            long n = in.nextLong();
            long m = in.nextLong();
            long ans = 0;
            long sum = 0;
            long div = n / m;
            long mod = div % 10;
            long times = div / 10;
            for (int j = 1; j <= 10; j++) {
                if(mod == j - 1){
                    ans += sum;
                }
                sum += (m * j) % 10;
            }
            ans += (times * sum);
            out.println(ans);
        }
        out.close();
    }
}