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
queries = int(input())

for i in range(queries):
    total_pages, m = [int(i) for i in input().split()]
    seq_last_digits = []

    # Criando a lista da sequencia padrao 
    i = m
    sum_seq = 0
    while True:
        last_digit = i % 10
        seq_last_digits.append(last_digit)
        sum_seq += last_digit
        if last_digit == 0:
            break
        else:
            i += m

    # Fazendo a conta
    qtd_nums_to_sum = total_pages // m
    mult = qtd_nums_to_sum // len(seq_last_digits)
    rest = qtd_nums_to_sum % len(seq_last_digits)

    output = mult * sum_seq
    for i in range(rest):
        output += seq_last_digits[i]

    print(output)

  			  			      		  		  	 	