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.StringTokenizer;
    import java.io.PrintWriter;
    import java.util.ArrayList;
    import java.util.List;
    import java.util.HashMap;
    import java.util.TreeMap;
    import java.util.Map;
    import java.util.Arrays;
    import java.util.Set;
    import java.util.HashSet;
    import java.util.Iterator;
    import java.util.Collections;
    import java.util.LinkedList;
    import java.util.Stack;
    
    /*
     *
     *  @author Riddle
     *
     */

    public final class BookReading
    {
        final static long MOD = (long)1e9+7;

        static class Pair
        {
            int first;
            int second;
            public Pair(int first, int second)
            {
                this.first = first;
                this.second = second;
            }

            @Override
            public boolean equals(Object obj)
            {
                Pair p = (Pair)obj;
                return p.first==first && p.second==second;
            }
        }
        
        static class FastReader
        {
            BufferedReader br;
            StringTokenizer st;
     
            public FastReader()
            {
                br = new BufferedReader(new
                         InputStreamReader(System.in));
            }
     
            String next()
            {
                while (st == null || !st.hasMoreElements())
                {
                    try
                    {
                        st = new StringTokenizer(br.readLine());
                    }
                    catch (IOException  e)
                    {
                        e.printStackTrace();
                    }
                }
                return st.nextToken();
            }
     
            int nextInt()
            {
                return Integer.parseInt(next());
            }
     
            long nextLong()
            {
                return Long.parseLong(next());
            }
     
            double nextDouble()
            {
                return Double.parseDouble(next());
            }
     
            String nextLine()
            {
                String str = "";
                try
                {
                    str = br.readLine();
                }
                catch (IOException e)
                { 
                    e.printStackTrace();
                }
                return str;
            }
        }

        public static void main(String args[])
        {
            FastReader reader = new FastReader();
            PrintWriter out = new PrintWriter(System.out);
            int test = reader.nextInt();
            for(int t =0;t<test;t++)
            {
                long n = reader.nextLong();
                long m = reader.nextLong();
                long count = n/m;
                long total = 0;
                if(m%10==0)
                {
                    out.println(0);
                    continue;
                }
                if(count==0)
                {
                    out.println(0);
                    continue;
                }
                if(m%2==0)
                {
                    long set = count/5;
                    total += 20*set;
                    long remain = count%5;
                    for(long i=1;i<=remain;i++)
                    {
                        long temp = i*m;
                        total += (temp%10);
                    }
                    out.println(total);
                }
                else
                {
                    long temp = 0;
                    for(long i=1;i<=10;i++)
                    {
                        temp += ((i*m)%10);
                    }
                    long remain = count/10;
                    total += temp*remain;
                    remain = count%10;
                    for(long i=1;i<=remain;i++)
                    {
                        temp = i*m;
                        total += (temp%10);
                    }
                    out.println(total);
                }
            }
            out.flush();        
            out.close();
        }

    }