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 Main {

	public static long[] auxSeq(long nPages, long divisor) {
		int baseSeq = 0;
		int baseSeqLength = 0;
		if(divisor%10==0) {
			baseSeq = 0;
		} else if (divisor%10==5) {
			baseSeq = 5;
			baseSeqLength = 2;
		} else if(divisor%10%2==0) {
			baseSeq = 20;
			baseSeqLength = 5;
		} else {
			baseSeq = 45;
			baseSeqLength = 10;
		}
		long nCycles = nPages/divisor/baseSeqLength;
		long[] ans = {baseSeq*nCycles, divisor*nCycles*baseSeqLength};
		return ans;
	}

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer tk;
		long nCases = Integer.parseInt(br.readLine()), nPages, divisor, ans, actualPage;
		for (int i = 0; i < nCases; i++) {
			ans = 0;
			tk = new StringTokenizer(br.readLine());
			nPages = Long.parseLong(tk.nextToken());
			divisor = Long.parseLong(tk.nextToken());
			if(divisor%10==0) {
				System.out.println(0);
				continue;
			}
			long[]auxSeqReturn = auxSeq(nPages, divisor);
			ans = auxSeqReturn[0];
			actualPage = auxSeqReturn[1]+divisor;
			for (long j = actualPage; j <= nPages; j += divisor) {
				ans += j % 10;
			}
			System.out.println(ans);
		}
		br.close();
	}
}
