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 BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));

	public static void main(String[] args) throws IOException {
		
		int cases = Integer.parseInt(bf.readLine());

		for (int j = 0; j < cases; j++) {

			StringTokenizer st;
			st = new StringTokenizer(bf.readLine());
			long paginas = Long.parseLong(st.nextToken());
			long divisor = Long.parseLong(st.nextToken());
			long patron = 0;
			long div = divisor%10;
			long pagina = divisor;
			long cont = 0;

			
			do {
				patron = patron + div;
				pagina+=divisor;
				div = pagina%10;
				cont ++;
			}
			while (divisor%10 != div && pagina <= paginas);
			
			long resultado = patron*(paginas/(divisor*cont));
			
			long restante = paginas%(pagina-divisor);
			cont = divisor;

			while (cont <= restante) {
				resultado += cont%10;
				cont+=divisor;
			}
			
			System.out.println(resultado);
			
		}

	}

}

		 	          				   	  	  				