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
# list input
def linp(): return list(map(int, input().split()))


# map input
def minp(): return map(int, input().split())


# int input
def iinp(): return int(input())


# no of testcase
def test(): return int(input())


# normal input
def inp(): return input()


def solve():
    # write your solution for one testcase
    n, m = map(int, input().split())
    pre = []
    for i in range(1, 11):
        k = m*i
        pre.append(k%10)
    # print(pre)
    m = m*10
    res = sum(pre) * (n//m)
    n = n%m
    res += sum(pre[:n//(m//10)])
    print(res)


def main():
    for _ in range(test()):
        solve()


if __name__ == '__main__':
    main()
