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.StringTokenizer;
import java.util.*;
import java.math.*; 
public class Solution {

    public static void main(String[] args) throws Exception {
        FastScanner cin = new FastScanner(System.in);
       int t = cin.nextInt();
       StringBuffer ans = new StringBuffer();
       while(t-->0)
       {
         long n = cin.nextLong();
         long m = cin.nextLong();
         long sum = 0;
         for(int i=1;i<=10;i++)
         {
           long temp = m*i;
           sum+=temp%10;
         }
         long div = n/m;
         long r = div%10;
         div = div/10;
         long a = div*sum;
         for(int i=1;i<=r;i++)
         {
            long temp = m*i;
            a+=temp%10;
         }
         ans.append(a+"\n");
       }
       System.out.print(ans);
  }
   

        
    static class FastScanner {
        private BufferedReader reader = null;
        private StringTokenizer tokenizer = null;
 
        public FastScanner(InputStream in) {
            reader = new BufferedReader(new InputStreamReader(in));
            tokenizer = null;
        }
 
        public String next() {
            if (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }
 
        public String nextLine() {
            if (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    return reader.readLine();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
 
            return tokenizer.nextToken("\n");
        }
 
        public long nextLong() {
            return Long.parseLong(next());
        }
         
        public int nextInt() {
            return Integer.parseInt(next());
        }
 
    }
  }   