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 Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int T = sc.nextInt();
		while(T-->0) {
			long n = sc.nextLong() , m = sc.nextLong();
			if(m>n) {System.out.println(0);continue;}
			int index = 0;
			int[] cyc = new int[20];
			for(int i = 0 ; i < cyc.length;i++)cyc[i]=0;
			boolean end = false;
			while(!end) {
				int a = ((int)(m%10) * (index + 1))%10;
				for(int i = 0 ; i < index ;i++)if(cyc[i]==a) {end = true;break;}
				if(!end)cyc[index++] = a;
			}
			//for(int i = 0 ; i < index ; i++)System.out.println(cyc[i]+" ");
			long add = n / m;
			int sum = 0;
			for(int i = 0 ; i < index ; i++)sum += cyc[i];
			long ans = sum * (add / index);
			long i = n / m % index;
			for(int j = 0 ; j < i ;j++)ans += cyc[j];
			System.out.println(ans);
		}

	}

}

	 			 	  	   	 		   	        		