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.util.stream.Collectors;

public class Main {

    public static void main(String args[]){
        Scanner scanner = new Scanner(System.in);

        int numberOfInputs = scanner.nextInt();
        scanner.nextLine();

        for(int i = 0; i < numberOfInputs; i++){
            String tupleToRead =  scanner.nextLine();
            String[] chipLocationsNumeric = tupleToRead.split("\\s+");
            List<Long> prices = Arrays.stream(chipLocationsNumeric).map(string -> Long.parseLong(string)).collect(Collectors.toList());
            System.out.println(findSumOfLastDigits(prices.get(0), prices.get(1)));
        }
    }

    public static long findSumOfLastDigits(Long numberOfPages, Long divisor){
        if(divisor > numberOfPages){
            return 0;
        }
        long sum = 0;
        Set<Long> uniqueLoop =  new HashSet<>();
        for(long i = 0; i <= numberOfPages; i += divisor){
            long numberToCheck = i % 10;
            if(uniqueLoop.contains(numberToCheck)){
                break;
            } else {
                sum += numberToCheck;
                uniqueLoop.add(numberToCheck);
            }
        }

        long cycleLength = uniqueLoop.size();
        long cycle_value = sum;
        long numWrittenPages = numberOfPages / divisor;
        long num_cycles = numWrittenPages / cycleLength;

        long partial_sum = cycle_value * num_cycles;
        long remainder_position = num_cycles * cycleLength * divisor;

        for (long i = remainder_position; i < numberOfPages + 1; i += divisor) {
            partial_sum += i % 10;
        }
        return partial_sum;


//        long numberOfCycles = numberOfPages / (divisor * uniqueLoop.size());
//        sum = sum * numberOfCycles;
//
//        long remainder = numberOfPages - (numberOfCycles * (divisor * uniqueLoop.size()));
//        multiplier = 1;
//        for(long i = divisor; i < remainder; i= divisor * multiplier){
//            sum += i % 10;
//            multiplier++;
//        }
//
//        return sum;
    }
}
