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
q = int(input())
for i in range(q):
    n, m = map(int, input().split())
    if m % 10 == 0:
        print(0)
    else:
        period = 1
        sum = 0
        while (period * m) % 10 != 0:
            sum += (period * m) % 10
            period += 1
        period_len = period * m
        n_period = math.floor(n / period_len)
        remain = n - n_period * period_len
        sum2 = 0
        if m <= n:
            for j in range(n - remain, n + 1, m):
                sum2 += j % 10
        #debug stuff print("pl: {}\nnp: {}\nr: {}\nn - r: {}\nsum: {}\nsum2: {}".format(period_len, n_period, remain, n - remain, sum, sum2))
        print(n_period * sum + sum2)
