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
lastDigits = [[0], 
              [0, 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]]
for _ in range(int(input())):
    n, m = input().split()
    n, m = int(n), int(m)
    total = 0
    i = n//m
    l = len(lastDigits[m%10])
    q, r = i//l, i%l
    print(q*sum(lastDigits[m%10]) + sum(lastDigits[m%10][:r+1]))
    
