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.*;

public class marathon3{

	public static void main(String[] args) throws IOException{
		
			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
			int test = Integer.parseInt(br.readLine());
			
			while(test-- >0){
				
				String ss[] = br.readLine().trim().split(" ");
				
				long n = Long.parseLong(ss[0]);
				long m = Long.parseLong(ss[1]);
				
				long s = 0;
			
				for(int i=1;i<=10;i++){
					s += (m*i)%10;
				}
				
				//System.out.println(s);
				
				long x = n/m;
				
				long r = x%10;
				long q = (x/10);
				
				s = (q*s);
				
				for(long i=1;i<=r;i++){
					s += (m*i)%10;
				}
				
				System.out.println(s);
			}				
	}
}


