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.*;
import java.math.*;
import java.util.*;


// @author : Dinosparton [ SHIVAM BHUVA ]

public class test {
	 
	   static class Pair{ 
		   int x;
		   int y;
		   
		   Pair(int x,int y){ 
			   this.x = x;
			   this.y = y;
			   
		   }
	   }
	  
	   static class Compare { 
		   
		     void compare(Pair arr[], int n) 
		    { 
		        // Comparator to sort the pair according to second element 
		        Arrays.sort(arr, new Comparator<Pair>() { 
		            @Override public int compare(Pair p1, Pair p2) 
		            { 
		                return p1.x - p2.x; 
		            } 
		        }); 
		  
//		        for (int i = 0; i < n; i++) { 
//		            System.out.print(arr[i].x + " " + arr[i].y + " "); 
//		        } 
//		        System.out.println(); 
		    } 
		} 
	  
	   
	   public static void main(String args[]) { 
		
		   
		  Scanner sc = new Scanner(System.in);
		
		
		  int t= sc.nextInt();
	        while(t-->0) {
	 
	            long n=sc.nextLong();
	            
	            long m=sc.nextLong();
	            
	            long[] digit=new long[10];
	            
	            long ans =0;
	            for(int i=1;i<=10;i++){
	                digit[i-1]=(i*m)%10;
	                ans+=digit[i-1];
	            }
	            long div=n/m;
	            ans=(div/10)*ans;
	            for(int i=0;i<div%10;i++)
	                ans+=digit[i];
	            System.out.println(ans);
	 
	        }
	   }  
}  

	  



