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 Main {

    public static void main(String[] args)  {
    
        Scanner sc=new Scanner (System.in);
       int size=sc.nextInt();
       while(size-->0){
      long x=sc.nextLong();
       long z=sc.nextLong();
       if(x<z){System.out.println("0");}
       else if(x==z){
       String st=x+"";
           System.out.println(st.charAt(st.length()-1));
       }
       else {
           if(x<=(z*10)){
       long out=0;
       for(long i=z;i<=x;i+=z){
       String st=(i)+"";
       out+=Integer.parseInt(""+st.charAt(st.length()-1));
       }
           System.out.println(out);}
           else{
           long afdi=x/z;//after divide
              
           int sum=0;
            for(long i=1;i<=10;i++){
       String st=(i*z)+"";
     sum+=Integer.parseInt(""+st.charAt(st.length()-1));
       }
             
               long out=(afdi/10)*sum;
                sum=0;
         for(int i=1;i<=(afdi%10);i++){
                String st=(i*z)+"";
             sum+=Integer.parseInt(""+st.charAt(st.length()-1));}
                System.out.println(out+sum);
           }
         
       }
       }
        
      
      
     }}