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 Solution{
    public static void main(String args[]) throws IOException{
        Reader.init();
        int Q=Reader.nextInt();
        
        for(int q=0;q<Q;q++){
            long n=Reader.nextLong();
            long m=Reader.nextLong();
            
            long num=n/m;        //numbers divisible by m
            
            long table[]=new long[10];
            table[0]=m%10;
            long cumulative=m;
            for(int i=1;i<10;i++){
                cumulative+=m;
                table[i]=table[i-1]+cumulative%10;       //Cumulative Sum of terms
            }
            //System.out.println(Arrays.toString(table));
            long full=num/10;
            long partial=num%10;
            int p=Integer.parseInt(String.valueOf(partial));
            //System.out.println(full+" "+partial);
            long sum;
            
            if(p==0){
                sum=table[9]*full;
            }
            else{
                sum=table[9]*full + table[p-1];    
            }
            
            System.out.println(sum);    
        }
    }
}

class Reader {
    static BufferedReader reader;
    static StringTokenizer tokenizer;

    static void init() {
        reader = new BufferedReader(new InputStreamReader(System.in) );
        tokenizer = new StringTokenizer("");
    }

    static String next() throws IOException {
        while ( ! tokenizer.hasMoreTokens() ) {
            tokenizer = new StringTokenizer(reader.readLine() );
        }
        return tokenizer.nextToken();
    }

    static int nextInt() throws IOException {
        return Integer.parseInt( next() );
    }
	
    static double nextDouble() throws IOException {
        return Double.parseDouble( next() );
    }

    static long nextLong() throws IOException {
        return Long.parseLong( next() );
    }
    
}