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
import math
import sys
from collections import defaultdict

# input = sys.stdin.readline
rt = lambda: map(int, input().split())
ri = lambda: int(input())
rl = lambda: list(map(int, input().split()))


def main():
    q = ri()
    for _ in range(q):
        n, m = rt()
        period = set()
        x = 1
        while x*m <= n:
            d = (x*m) % 10
            if d in period:
                break
            period.add(d)
            x += 1

        if x*m > n:  # we have all
            res = sum(period)
        else:
            x -= 1
            biggestX = n // m
            res = sum(period) * (biggestX // x)
            currX = (biggestX // x) * x
            while currX*m <= n:
                res += (currX*m) % 10
                currX += 1
        print(res)


if __name__ == '__main__':
    main()
