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
/*
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 * and open the template in the editor.
 */
//package Contests;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 *
 * @author Akhilesh
 */
public class C1213 {
    public static void main(String[] args) throws IOException{
        BufferedReader scan = new BufferedReader(new InputStreamReader(System.in));
        int t = Integer.parseInt(scan.readLine().trim());
        String str[];
        long arr[] = new long[9];
        long sum = 0;
        while(t-- > 0){
            str = scan.readLine().split("\\s+");
            long n = Long.parseLong(str[0]);
            long m = Long.parseLong(str[1]);
            arr[0] = m%10;
            for(int i = 1; i < 9; i++){
                long val = m*(i+1);
                arr[i] = arr[i-1] + (val%10);
            }
            
            long mul = n/m;
            int mod = (int)(mul%10);
            
            sum = 0;
            if(mod != 0){
                sum += arr[mod-1];
            }
            
            sum += (mul/10)*arr[8];
            
            System.out.println(sum);
        }
    }
}
