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.*;

public class JavaApplication56 {
    
    public static long su(long y){
        String s = y + "";
        s = s.charAt(s.length()-1) + "";
        return Long.parseLong(s);
    }
    
    public static void main(String[] args) {
        Scanner inp = new Scanner(System.in);
        
        int q = inp.nextInt();
        for (int oooooo = 0; oooooo < q; oooooo++) {
            long n = inp.nextLong();
            long m = inp.nextLong();
            long t = m;
            long total = 0;
            
            for (int i = 0; i < 10; i++) {
                if (t > n){
                    break;
                }
                total += su(t);
                t += m;
                
            }
            t = t - m;
            //System.out.println("t: " + t);
           long times = (n / (m*10));
            
            
            
            if (times == 0){
                System.out.println(total);
                continue;
            }
            
            
            else{
                t = t * (times);
                total = total * times;
                //System.out.println(t + " -- " + total);
                for (int i = 0; i < 10; i++) {
                    //System.out.println("-----" + total);
                    if (t > n){
                        //System.out.println(t + " -- " + n);
                        break;
                    }
                    total += su(t);
                    t += m;
                
                }
            }
            //times--;
            //
            
            System.out.println(total);
            //System.out.println(times);
            //System.out.println("-----");
            
            
        }
    }
    
}
