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
t=int(input())
for _ in range(t):
	n,m=map(int,input().split())
	if(n==m):
		print(n%10);
		continue;
	if(n<m):
		print(0);
		continue;
	sum=0
	f=0
	for i in range(1,11):
		if(n-(m*i)<0): 
			f=1
			break
		sum=sum+(m*i)%10
	if(f==1):
		print(sum)
		continue
	res=0
	k=(int)((n+m-1)/m/10)
	mm=m*k*10
	res=sum*k
	for i in range(1,11):
		if(n-(mm+i*m)<0):
			break
		res=res+(mm+i*m)%10
	print(res)