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 last_digit(num):
    return num % 10


q = int(input())

for i in range(q):
    s = 0
    n, m = map(int, input().split())
    j = m
    while j < (m*10) and j <= n:
        s += last_digit(j)
        j += m
    if (m*10) < n:
        nn = n // (m*10)
        s = s * nn
        j = n % (m*10)
        k = m
        while k <= j:
            s += last_digit(k)
            k += m
        print(s)
    else:
        print(s)