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.*;
import java.util.*;
public class C{
    public static void main(String[] args){
        InputReader reader = new InputReader();
        PrintWriter writer = new PrintWriter(new BufferedOutputStream(System.out));
        // your program goes here
        int t = reader.nextInt();
        while(t-- > 0){
            long n = reader.nextLong();
            long m = reader.nextLong();
            long ans = 0;
            if(n>=m){
                long i = 1;
                long initSum = 0;
                long divVal = 0;
                while(true){
                    long tempVal = i * m;
                    i++;
                    if(tempVal>n)
                        break;
                    initSum += tempVal%10;
                    if(tempVal%10==0){
                        divVal = tempVal;
                        break;
                    }
                }
                if(divVal==0)
                    ans = initSum;
                else{
                    long coef = n/divVal;
                    ans = initSum * coef;
                    long j = (coef * divVal)/m;
                    while(true){
                        long tempVal = j * m;
                        j++;
                        if(tempVal>n)
                            break;
                        ans += tempVal%10;
                    }
                }
            }
            writer.println(ans);
        }
        writer.close();
    }
    static class InputReader{
        BufferedReader br;
        StringTokenizer tokenizer;

        InputReader(){
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        public String next(){
            while(tokenizer==null || !tokenizer.hasMoreElements()){
                try{
                    tokenizer = new StringTokenizer(br.readLine());
                }catch(IOException e){
                    e.printStackTrace();
                }
            }
            return tokenizer.nextToken();
        }

        public Integer nextInt(){
            return Integer.parseInt(next());
        }

        public Long nextLong(){
            return Long.parseLong(next());
        }

        public Double nextDouble(){
            return Double.parseDouble(next());
        }

        public String nextLine(){
            String str = "";
            try{
                str = br.readLine();
            }catch(IOException e){
                e.printStackTrace();
            }
            return str;
        }
    }
}
