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
n = int(input());
lista = [[0],[1,2,3,4,5,6,7,8,9,0],[2,4,6,8,0],[3,6,9,2,5,8,1,4,7,0],[4,8,2,6,0],[5,0],[6,2,8,4,0],[7,4,1,8,5,2,9,6,3,0],[8,6,4,2,0],[9,8,7,6,5,4,3,2,1,0]]
soma = [[0],[sum(lista[1])],[sum(lista[2])],[sum(lista[3])],[sum(lista[4])],[sum(lista[5])],[sum(lista[6])],[sum(lista[7])],[sum(lista[8])],[sum(lista[9])]]
while(n):
	res = 0;
	x,y = map(int,input().split())
	div = x//y;
	y = str(y); ultimoD = y[len(y)-1];ultimoD = int(ultimoD); y = int(y);
	nCiclo = div//len(lista[ultimoD]);
	resto = div%len(lista[ultimoD])
	res+=nCiclo*soma[ultimoD][0];
	for i in range(resto):
		res+=lista[ultimoD][i];
	print(res);
	n-=1;
	     	  	    		     					 				