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

def get_till_10(m):
    out =  [(m * i)%10 for i  in range(1, 11)]
    return sum(out), out


def handle_case(n, m):
    if n < m:
        print(0)
        return

    k = n // (m*10)
    # print(k)
    sum_till_10, arr_till_10 = get_till_10(m)
    # print(sum_till_10)
    remain = (n - k * m * 10) // m
    # print(remain)
    out = sum_till_10 * k + sum(arr_till_10[:remain])

    print(out)
    


def run():
    num_queries = eval(input())
    queries = []
    for _ in range(num_queries):
        queries.append(list(map(int, input().split())))

    for query in queries:
        n, m = query
        handle_case(n, m)

if __name__ == "__main__":
    run()