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.util.*;
import java.io.*;

public class MyClass {
    public static void main(String args[]) throws Exception{
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        int t=Integer.parseInt(br.readLine());
      
        for(int j=0;j<t;j++){
            String[] str=br.readLine().split(" ");
            
            long n=Long.parseLong(str[0]);
            long m=Long.parseLong(str[1]);
            long cnt=0;
            
            long c=1;
            long x=1;
            while(c%10!=0){
                c=m*x;
                x++;
            }
            
            if(n>c){
                List<Long> ll=new ArrayList<Long>();
                int ia=1;
                while((ia*m)%10!=0){
                    ll.add(m*ia);
                    ia++;
                }
                
                long a=n/c;
                long b=n%c;
                
                for(int i=0;i<ll.size();i++){
                    cnt+=ll.get(i)%10;
                }
                cnt=cnt*a;
                
                int ib=1;
                while((ib*m)<=b){
                    cnt+=(ib*m)%10;
                    ib++;
                }
            }
            else{
                int ib=1;
                while((ib*m)<=n){
                    cnt+=(ib*m)%10;
                    ib++;
                }
            }
            
            System.out.println(cnt);
            
        }
    }
    
}