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
/*package whatever //do not write package name here */

import java.io.*;
import java.util.*;

public class GFG {
	public static void main (String[] args) throws IOException {
	    BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
	    StringTokenizer st=new StringTokenizer(br.readLine());
	    int q=Integer.parseInt(st.nextToken());
	  for(int z=1;z<=q;z++)
	  {
	      st=new StringTokenizer(br.readLine());
	      long n=Long.parseLong(st.nextToken());
	      long m=Long.parseLong(st.nextToken());
	      //System.out.println(n);
	      //System.out.println(n/m);
	      if(n<m)
	      {
	        System.out.println("0");
	      }
	      else
	      {
	          long x=n/m;
	          if(x<=10)
	          {
	             long ans=0;
	          long j=1;
	          while(j*m<=n)
	          {
	            ans+=(j*m)%10;
	            j++;
	          }
	          System.out.println(ans); 
	          }
	          else{
	          long sum=0;
	          long j=1;
	          while(j<=10)
	          {
	            sum+=(j*m)%10;
	            j++;
	          }
	          long ans=sum*(x/10);
	          long c=x%10;
	          j=1;
	          sum=0;
	          while(j<=c)
	          {
	            sum+=(j*m)%10;
	            j++;
	          }
	          ans+=sum;
	          System.out.println(ans);
	          }
	      }
	  }
	   
	        }
	    }
	       
	   
