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.Scanner;

public class S {
	public static void main(String[] args) {
		Scanner scanner=new Scanner(System.in);
		int t=scanner.nextInt();
		StringBuilder ans=new StringBuilder();
		long n,m,sum,bit,cnt;
		while(t-->0){
			n=scanner.nextLong();
			m=scanner.nextLong();
			cnt=n/m;
			m%=10;
			sum=0;
			bit=0;
			if(cnt==0){
				ans.append(0+"\n");
				continue;
			}else if(cnt>=10){
				for(int i=0;i<10;i++){
					bit+=((i*m)%10);
				}
				sum+=bit*(cnt/10);
				cnt%=10;
			}
			for(int i=0;i<=cnt;i++){
				sum+=(i*m)%10;
			}
//			System.out.println(n+" "+m+" "+sum);
			ans.append(sum+"\n");
		}
		System.out.print(ans);
	}
}
