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
/* package codechef; // don't place package name! */

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


/* Name of the class has to be "Main" only if the class is public. */
public class Codechef
{
         static class Input {
        private StringTokenizer tokenizer = null;
        private BufferedReader reader;
 
        public Input(InputStream inputStream) {
            reader = new BufferedReader(new InputStreamReader(inputStream));
        }
 
        public String nextLine() {
            try {
                return reader.readLine();
            } catch (IOException e) {
                throw new RuntimeException();
            }
        }
 
        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                tokenizer = new StringTokenizer(nextLine());
            }
            return tokenizer.nextToken();
        }
 
        public int nextInt() {
            return Integer.parseInt(next());
        }
 
        public long nextLong() {
            return Long.parseLong(next());
        }
 
        public int[] nextIntArray(int n, int add) {
            int[] result = new int[n];
            for (int i = 0; i < n; i++) {
                result[i] = nextInt() + add;
            }
            return result;
        }
 
        public long[] nextLongArray(int n, long add) {
            long[] result = new long[n];
            for (int i = 0; i < n; i++) {
                result[i] = nextLong() + add;
            }
            return result;
        }
 
        public int[] nextIntArray(int n) {
            return nextIntArray(n, 0);
        }
 
    }
    
	public static void main (String[] args) throws java.lang.Exception
	{
		Input s=new Input(System.in);
		int t=s.nextInt();
		PrintWriter out=new PrintWriter(System.out);
		
		while(t-->0)
		{
		    long n=s.nextLong();
		    long m=s.nextLong();
		    int r=(int)(m%10);
		    ArrayList<Integer> arr=new ArrayList<>();
		    int l=r;
		    long sum=0;
		    while(l!=0)
		    {
		        sum+=l;
		        arr.add(l);
		        l=(l+r)%10;
		    }
		    arr.add(0);
		    
		    long div=n/m;
		    
		    long ans=sum*(div/arr.size());
		    for(int i=0;i<div%arr.size();i++)
		    {
		        ans+=arr.get(i);
		    }
		    System.out.println(ans);
		}
	}
}
