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
from sys import stdin

inp = stdin.readline
t = int(inp().strip())
for _ in range(t):
    n, m = [int(x) for x in inp().strip().split()]
    if n < m:
        print(0)
    else:
        maxNum = -1
        i = 0
        lastDigit = []
        while True:
            num = m*i
            if num%10 in lastDigit:
                maxNum = num
                break
            else:
                lastDigit.append(num%10)
            i += 1
        sumOfDigits = sum(lastDigit)
        ans = (n//maxNum)*sumOfDigits
        num = 0
        i = 0
        rem = n%maxNum
        while True:
            num = m * i
            if num > rem:
                break
            ans += num % 10
            i += 1

        print(ans)