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.io.*;
 import javafx.util.Pair; 
 
 public class Param
{
          
      public static  void main( String[]args) 
    {
       
      Scanner param=new Scanner(System.in);
      int end=param.nextInt();
      while(end>0){
         end--;
      
    long n=param.nextLong();
      long m=param.nextLong();
      ArrayList<Integer>l1=new ArrayList<Integer>();
      HashSet<Integer>h=new HashSet<>();
      long sum=0;
     
      long a[]=new long[10];
      long cycle=n/m;
      int j=0;
     
      for (int i = 0; i < 10; i++) {
			a[i] = m * (i + 1) % 10;
			sum += a[i];
		}
 
        
        
     
      long ans=sum*(cycle/10);
    
     
      for(int i=0;i<cycle%10;i++){
         ans+=a[i];
      }
      System.out.println(ans);
        
      }
}
}