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
q = int(input())
v = [[1, 2, 3, 4, 5, 6, 7, 8, 9, 0],
[2, 4, 6, 8, 0],
[3, 6, 9, 2, 5, 8, 1, 4, 7, 0],
[4, 8, 2, 6, 0],
[5, 0],
[6, 2, 8, 4, 0],
[7, 4, 1, 8, 5, 2, 9, 6, 3, 0],
[8, 6, 4, 2, 0],
[9, 8, 7, 6, 5, 4, 3, 2, 1, 0]]
for i in range(q):
    x, y = map(int, input().split())
    y1 = y%10
    s = x//y
    f = s//len(v[y1 - 1])
    c = s%len(v[y1 - 1])
    if y1==0:
        print(0)
    else:
        d = f*(sum(v[y1-1])) + sum(v[y1 - 1][:c:])
        print(d)
