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.ArrayList;
import java.util.Arrays;
import java.util.StringTokenizer;

public class C1213   {
    public static void main(String[] args) throws IOException {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        int q=Integer.parseInt(br.readLine());
        long ans[]=new long[q];
        int n=0;
        while(q>0)
        {
            StringTokenizer s=new StringTokenizer(br.readLine());
            long a=Long.parseLong(s.nextToken());
            long d=Long.parseLong(s.nextToken());
            if (d>a){
                ans[n]=0;
            }
            if (d==a){
                ans[n]=d%10;
            }
            else {
                long sum = 0;
               long al[]=new long[10];
                for (int i = 0; i <10 ; i++) {
                    al[i]=((i + 1) *d) % 10;
                }
                for (int i=0;i<10;i++)
                {
                    sum+=al[i];
                }

                long toal = sum*((a/d)/10);

                        for (int i = 0; i < (a/d)%10; i++) {
                            toal += al[i];
                        }
                    ans[n] = toal;

            }

                n++;
                q--;

        }
        for (long b:
             ans) {
            System.out.println(b);
        }
    }
}
