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.math.BigInteger;
import java.util.*;
import java.io.*;
import java.util.Map.Entry;

public class Codeforces {


    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw = new PrintWriter(System.out);
        int t = Integer.parseInt(br.readLine());
        ArrayList<Integer>[] arr = new ArrayList[10];
        for (int i = 0; i < 10; i++) {
            arr[i] = new ArrayList<>();
        }
        for (int i = 1; i < 10; i++) {
            int tmp = i;
            int sum = 0;
            while (tmp % 10 != 0) {
                arr[i].add(tmp % 10);
                sum += tmp % 10;
                tmp += i;
            }
            arr[i].add(tmp / i);
            arr[i].add(sum);
        }
        while (t-- > 0) {
            StringTokenizer st = new StringTokenizer(br.readLine());
            long n = Long.parseLong(st.nextToken());
            long m = Long.parseLong(st.nextToken());
            String M = m +"";
            int num = Integer.parseInt(M.charAt(M.length() - 1) + "");
            if(num == 0){
                pw.println(0);
                continue;
            }
            long sum = 0;
            sum += (n / (m * arr[num].get(arr[num].size() - 2))) * arr[num].get(arr[num].size() - 1);
            long mod = n % (m * arr[num].get(arr[num].size() - 2));
            int idx = 0;
            long c = m;
            while(c <= mod){
                sum += arr[num].get(idx);
                idx++;
                c += m;
            }
            pw.println(sum);
        }
        pw.flush();
        pw.close();
    }
}