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
from typing import List

q = int(input())


def getCLen(x: int) -> List[int]:
    cycle = []
    i = x
    while True:
        if i in cycle:
            return cycle
        cycle.append(i)
        i += x
        i %= 10


cLen = [getCLen(x) for x in range(10)]
# print(cLen)
for _ in range(q):
    n, m = map(int, input().strip().split())
    if n < m:
        print(0)
    else:
        cycle = cLen[m % 10]
        result = ((n // m) // len(cycle) * sum(cycle)) + sum(cycle[:(n // m) % len(cycle)])
        print(result)


"""
3, 6, 9, 2, 5, 8, 1, 4, 7, 0, 3
4, 8, 2, 6, 0, 
9, 8, 7, 6, 5, 4, 3, 2, 1, 0
"""