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;
import java.util.StringTokenizer;

public class E {

	public static void main(String[] args) throws NumberFormatException, IOException {
		BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
		int casos=Integer.parseInt(bf.readLine());
		long n,m,sum,tam,result,temp,pb,t;
		StringTokenizer tk;
		for (int i = 0; i < casos; i++) {
			tk=new StringTokenizer(bf.readLine());
			n=Long.parseLong(tk.nextToken());
			m=Long.parseLong(tk.nextToken());
			sum=0;
			tam=0;
			result=0;
			temp=0;
			if(m>n) {
				System.out.println("0");
			}else if(m==n) {
				System.out.println(m%10);
			}else {
				for (int j = 0; j < 10; j++) {
					sum+=temp%10;
					temp+=m;
					tam=temp;
				}
				t=(long) ((n)/(tam));
				result=(long) (sum*t);
				pb=(tam)*t;
				while(pb<=(n-m)) {
					pb+=m;
					result+=pb%10;
				}
				System.out.println(result);
			}
		}
	}

}

				 			 		 		   			 	 			  	