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.InputStreamReader;
import java.util.StringTokenizer;

public class Round582_3_c {
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st;

        int t = Integer.parseInt(br.readLine());

        while(t-->0) {
            st = new StringTokenizer(br.readLine());
            long n = Long.parseLong(st.nextToken());
            long d = Long.parseLong(st.nextToken());

            long times = n/d;
            long sum = 0;

            long ans = 0;

            long a[] = new long[11];
            for(int i=1 ; i<=10 ; i++) {
                a[i] = (i*d)%10;
                sum += a[i];
            }

            if(times >= 10) {
                ans = sum * (times/10);
                times %= 10;
            }

            for(int i=1 ; i<=times ; i++) {
                ans += a[i];
            }

            System.out.println(ans);
        }
    }
}
