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.*;
import java.util.*;

public class C
{
    PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer tok;

    public void go() throws IOException
    {
        StringTokenizer tok = new StringTokenizer(in.readLine());
        int zzz = Integer.parseInt(tok.nextToken());
        for (int zz = 0; zz < zzz; zz++)
        {
            ntok();
            long n = lpar();
            long m = lpar();
            if (n < m)
            {
                out.println(0);
                continue;
            }
            boolean[] seen = new boolean[10];
            long curr = m;
            long sum = 0;
            while (curr <= n)
            {
                if (seen[(int)(curr%10)])
                {
                    break;
                }
                seen[(int)(curr%10)] = true;
                sum += curr % 10;
                curr += m;
            }
            sum *= n / (curr - m);
            curr = n / (curr - m) * (curr - m) + m;
            while (curr <= n)
            {
                sum += curr%10;
                curr += m;
            }
            out.println(sum);
        }

        out.flush();
        in.close();
    }

    public void ntok() throws IOException
    {
        tok = new StringTokenizer(in.readLine());
    }

    public int ipar()
    {
        return Integer.parseInt(tok.nextToken());
    }

    public long lpar()
    {
        return Long.parseLong(tok.nextToken());
    }

    public double dpar()
    {
        return Double.parseDouble(tok.nextToken());
    }

    public String spar()
    {
        return tok.nextToken();
    }

    public static void main(String[] args) throws IOException
    {
        new C().go();
    }
}
