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
# Contest: Codeforces Round #582 (Div. 3) (https://codeforces.com/contest/1213)
# Problem: C: Book Reading (https://codeforces.com/contest/1213/problem/C)

def rint():
    return int(input())


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


from math import gcd
q = rint()
for _ in range(q):
    n, m = rints()
    lcm = 10 * m // gcd(10, m)
    block = 0
    for i in range(lcm // m):
        block += (i + 1) * m % 10
    n_block = n // lcm
    tot = n_block * block
    for i in range(n_block * lcm, n + 1, m):
        tot += i % 10
    print(tot)
