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.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.stream.Collectors;

public class C{
	
	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; 
        } 
    }
	
	static long gcd(long a, long b) 
    { 
        if (b == 0) 
            return a; 
        return gcd(b, a % b); 
    } 
	public static void main(String[] args) 
	{
		OutputStream outputStream = System.out;
        FastReader sc = new FastReader();
        PrintWriter out = new PrintWriter(outputStream);
        
        int q = sc.nextInt();
        while(q-- > 0)
        {
        	long n = sc.nextLong();
        	long m = sc.nextLong();
        	
        	long ct = n/m;
        	
        	long r = m%10;
        	
        	long cp = r;
        	long len = 0;
        	cp += r;
        	cp = cp%10;
        	len = 1;
        	long sum = 0;
        	sum += cp;
        	while(cp != r)
        	{
        		cp += r;
        		cp = cp%10;
        		sum += cp;
        		len++;
        	}
        	//out.println("len "+len);
        	//out.println("sum "+sum);
        	long ans = ((long)ct/len)*sum;
        	
        	long rem = ct%len;
        	
        	cp = r;
        	
        	while(rem-- > 0)
        	{
        		ans += cp;
        		cp += r;
        		cp = cp%10;
        	}
        	
        	out.println(ans);
        }
        
        
        out.close();
	}
}