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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class books {
	public static void main(String args[])throws IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		int cases=Integer.parseInt(in.readLine());
		for(int c=0;c<cases;c++) {
			String[] line=in.readLine().split(" ");
			long n=Long.parseLong(line[0]);
			long m=Long.parseLong(line[1]);
			long k=n/m;
			long ans=0;
			for(int i=1;i<=10;i++) {
				ans+=(i*m)%10;
			}
			ans*=k/10;
			for(int i=1;i<k%10+1;i++) {
				ans+=(i*m)%10;
			}
			System.out.println(ans);
		}
	}
}
