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.InputStreamReader;
import java.util.*;



public class Test {
  
   
    public static void main(String args[])  throws Exception{
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        int t = Integer.parseInt(in.readLine());
        while(t-- > 0){
            String S[] = in.readLine().split(" ");
            long n  = Long.parseLong(S[0]);
            long m = Long.parseLong(S[1]);
            long div = n/m;
            long round = div/10;
            long re = div%10;
            long sum = 0;
            long s = 0;
            for(long i = 1; i <= re; i++){
                s += m;
                sum = sum + s%10;
            }
            long ans = sum;
            for(long i = re+1; i <= 10; i++){
                s += m;
                sum = sum + s%10;
            }
            
            ans += sum*round;

            System.out.println(ans);
        }
    }
}