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
q = int(input())
answers = []

for ti in range(q):
    ints = list(map(int, input().split()))
    n, m = ints[0], ints[1]

    digits = {}
    mult = 1
    while True:
        s = str(mult * m)
        mult += 1
        digit = int(s[-1])
        if digit in digits:
            break
        digits[digit] = 1

    digits = list(digits.keys())
    total = 0
    mult = n // m // len(digits)
    
    for i in range(len(digits)):
        total += mult * digits[i]

    rem = n // m % len(digits)
    for i in range(rem):
        total += digits[i]

    rem = n % m

    answers.append(total)

for a in answers:
    print(a)
