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 bookreading{
	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 sc=new FastReader();
	int t=sc.nextInt();
	while(t-->0){
		long n=sc.nextLong();
		long k=sc.nextLong();
		long no_of_div;
		long ans=0;
		if((n-k)<0)
			ans=0;
		else if((n-k)==0)
			ans=k%10;
		else{
	no_of_div=	(n - (1 - 1 % k)) / k ;
	if(k==1)
		no_of_div++;
				long a[]=new long[10];
				
				int sum=0;
				for(int i=1;i<=10;i++){
					a[i-1]=(long)(k*(long)i)%(long)10;
					sum+=a[i-1];
				}
				
				ans=(no_of_div/10)*sum;
			for(int i=0;i<(no_of_div)%10;i++){
				ans+=a[i];
			}
		}
		System.out.println(ans);
	}
}
}