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.*;

public class BookReading{
    
    public static void main(String[] args){
    	Scanner input = new Scanner(System.in);
    	int t = input.nextInt();
    	while(t-->0) {
    		long n = input.nextLong();
    		long m = input.nextLong();
    		
    		if(m>n) {
    			System.out.println(0);
    			continue;
    		}
    		else {
    			long[] a = new long[10];
    			a[0] = m%10;
    			for(int i=1;i<=9;i++) {
    				long v = m*(i+1);
    				//System.out.print(v+" ");
    				a[i] = v%10 + a[i-1];
    			}
    			
    			long v = m*10;
    			long ans = (n/v)*a[9];
    			//System.out.println(n%v);
    			if(n%v != 0 && n%v >= m) ans += a[(int)((n%v)/m-1)];
    			System.out.println(ans);
    		}
    	}
    }
}