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
    // No sorceries shall previal. //
         
    import java.util.Scanner; 
    import java.io.PrintWriter;
    import java.util.*;
    import java.util.Arrays;
     
    public class InVoker {
    		
    	public static void main(String args[]) {
    		
    		Scanner inp = new Scanner(System.in);
    		PrintWriter out= new PrintWriter(System.out);
    		
    		int q=inp.nextInt();
    		while(q-->0)
    		{
    			long n=inp.nextLong();
    			long m=inp.nextLong();
    			if(m>n)
    			{
    				out.println(0);
    				continue;
    			}
    			long sum=0;
    			long temp=m*2;
    			while(temp%10!=m%10)
    			{
    				sum+=temp%10;
    				temp+=m;
    			}
    			temp-=m;
    			sum+=m%10;
    			sum*=(n/temp);
    			n-=(temp*(n/temp));
    			
    			temp=m;
    			while(n>=temp) {
    				sum+=temp%10;
    				temp+=m;
    			}
    			out.println(sum);
    		}
    		
    		
    		out.close();
    		inp.close();
    					
    }
    		
}