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
array0 = [0]
array1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
array2 = [2, 4, 6, 8, 0]
array3 = [3, 6, 9, 2, 5, 8, 1, 4, 7, 0]
array4 = [4, 8, 2, 6, 0]
array5 = [5, 0]
array6 = [6, 2, 8, 4, 0]
array7 = [7, 4, 1, 8, 5, 2, 9, 6, 3, 0]
array8 = [8, 6, 4, 2, 0]
array9 = [9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
array = [array0, array1, array2, array3, array4, array5, array6, array7, array8, array9]

q = int(input())

for _ in range(q):
    n, m = input().split()
    m_last = int(m[-1])
    m, n = int(m), int(n)
    count = n // m
    quot = count // len(array[m_last])
    rem = count % len(array[m_last])
    total = quot * sum(array[m_last]) + sum(array[m_last][:rem])
    print(total)
