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 sys
import math
from copy import deepcopy
from collections import deque, defaultdict
from operator import mul
from functools import reduce
sys.setrecursionlimit(20000000)

input = sys.stdin.readline


def main():
    q = int(input())

    for _ in range(q):
        n, m = map(int, input().split())
        nums = n // m
        ans = 0

        set = nums // 10

        nums = nums - (set * 10)

        m = int(str(m)[-1])

        if set:
            sm = 0
            tmp = m
            for _ in range(10):
                sm += tmp
                tmp += m
                tmp = int(str(tmp)[-1])
            ans = sm * set

        sm = 0
        tmp = m
        for _ in range(nums):
            sm += tmp
            tmp += m
            tmp = int(str(tmp)[-1])

        ans += sm

        print(ans)


if __name__ == '__main__':
    main()
