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 Main
{
    public static void main (String [] args) throws Exception
    {
        Scanner sc = new Scanner() ;
        PrintWriter out = new PrintWriter(System.out) ;
        int t = sc.nextInt() ;
        while (t-->0)
        {
            long n = sc.nextLong() ;
            long m = sc.nextLong() ;
            boolean [] vis = new boolean[100] ;
            int [] cyc = new int[100] ;
            int ptr = 0 ;
            for(long i = 0 ; !vis[(int)(i % 10)] ;i += m)
                vis[cyc[ptr++] = (int)(i % 10)] = true ;
            long ans = 0 ;
            long div = (n / m) / ptr ;
            for (int i = 0; i < ptr; i++)
                ans += cyc[i] * div;
            for (int i = 0; i <= ((n / m) % ptr); i++)
                ans += cyc[i];

            out.println(ans);
        }
        out.flush();
    }
    static class Scanner
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in)) ;
        StringTokenizer st ;

        String next() throws Exception
        {
            while (st == null || !st.hasMoreTokens())
                st = new StringTokenizer(br.readLine()) ;
            return st.nextToken() ;
        }
        int nextInt() throws Exception
        {
            return Integer.parseInt(next()) ;
        }
        long nextLong () throws Exception
        {
            return Long.parseLong(next()) ;
        }
    }

}