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 Main {

    public static int binary(long arr[][], int l,int r,long b){

        int mid=l+(r-l)/2;

        if(arr[1][mid]>=b && arr[1][mid-1]<b){

            return mid;

        }

        if(arr[1][mid]>b){

            return binary(arr,l,mid-1,b);

        }

        return binary(arr,mid+1,r,b);

    }

    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);

        int q=scan.nextInt();

        for(int h=0;h<q;h++) {

            long n, m;

            n = scan.nextLong();

            m = scan.nextLong();

            Vector<Long> last = new Vector<>();

            last.add(m % 10);

            long sum=last.elementAt(0);

            for (long i = m * 2; last.elementAt(0) != i % 10; i += m) {

                last.add(i % 10);

                sum+=i%10;

            }

            long steps=(n/m)/last.size();

            sum*=steps;

            steps=n/m-steps*last.size();

            for(int i=0;i<steps;i++){

                sum+=last.elementAt(i);

            }

            System.out.println(sum);

        }

    }

}


