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 C1213{
	public static void main(String args[])throws IOException{
		Scanner sc=new Scanner(new BufferedReader(new InputStreamReader(System.in)));
		PrintWriter pw=new PrintWriter(System.out);
		int t=sc.nextInt();
		while(t--!=0){
			long n=sc.nextLong();
			long m=sc.nextLong();
			long m10=m*10;
			long sum=0;
			for(int i=1;i<11;i++){
				sum+=((m*i)%10);
			}
			long ans=0;
			ans=(sum*(n/m10));
			m10*=(n/m10);
			for(int i=1;i<11;i++){
				m10+=m;
				if(m10>n)
					break;
				ans+=(m10%10);
				
			}
			pw.println(ans);
		}
		pw.close();
	}
}