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.util.StringTokenizer;

public class problem3 {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        long sets = Long.parseLong(br.readLine());
        for(long j = 0; j<sets; j++) {
            StringTokenizer st = new StringTokenizer(br.readLine());
            long num = Long.parseLong(st.nextToken());
            long divisor = Long.parseLong(st.nextToken());
            long divisorDigit = (long) (divisor % 10);
            long quotient = (long) (num / divisor);
            if(divisorDigit==0){
                System.out.println(0);
            }
            if (divisorDigit == 1) {
                long sum = 0;
                long period = 10;
                long n = 1;
                long periodSum = 45;
                for (long i = 1; i <= quotient % period; i++) {
                    sum += (n * i) % 10;
                }
                System.out.println((quotient / period) * periodSum + sum);
            }
            else if (divisorDigit == 2) {
                long sum = 0;
                long period = 5;
                long n = 2;
                long periodSum = 20;
                for (long i = 1; i <= quotient % period; i++) {
                    sum += (n * i) % 10;
                }
                System.out.println((quotient / period) * periodSum + sum);

            } else if (divisorDigit == 3) {
                long sum = 0;
                long period = 10;
                long n = 3;
                long periodSum = 45;
                for (long i = 1; i <= quotient % period; i++) {
                    sum += (n * i) % 10;
                }
                System.out.println((quotient / period) * periodSum + sum);
            } else if (divisorDigit == 4) {
                long sum = 0;
                long period = 5;
                long n = 4;
                long periodSum = 20;
                for (long i = 1; i <= quotient % period; i++) {
                    sum += (n * i) % 10;
                }
                System.out.println((quotient / period) * periodSum + sum);
            } else if (divisorDigit == 5) {
                long sum = 0;
                long period = 2;
                long n = 5;
                long periodSum = 5;
                for (long i = 1; i <= quotient % period; i++) {
                    sum += (n * i) % 10;
                }
                System.out.println((quotient / period) * periodSum + sum);
            } else if (divisorDigit == 6) {
                long sum = 0;
                long period = 5;
                long n = 6;
                long periodSum = 20;
                for (long i = 1; i <= quotient % period; i++) {
                    sum += (n * i) % 10;
                }
                System.out.println((quotient / period) * periodSum + sum);
            } else if (divisorDigit == 7) {
                long sum = 0;
                long period = 10;
                long n = 7;
                long periodSum = 45;
                for (long i = 1; i <= quotient % period; i++) {
                    sum += (n * i) % 10;
                }
                System.out.println((quotient / period) * periodSum + sum);
            } else if (divisorDigit == 8) {
                long sum = 0;
                long period = 5;
                long n = 8;
                long periodSum = 20;
                for (long i = 1; i <= quotient % period; i++) {
                    sum += (n * i) % 10;
                }
                System.out.println((quotient / period) * periodSum + sum);
            } else if (divisorDigit == 9) {
                long sum = 0;
                long period = 10;
                long n = 9;
                long periodSum = 45;
                for (long i = 1; i <= quotient % period; i++) {
                    sum += (n * i) % 10;
                }
                System.out.println((quotient / period) * periodSum + sum);
            }
        }


    }
}
