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
 
'''
7
1 1
10 1
100 3
1024 14
998244353 1337
123 144
1234312817382646 13
'''
 
 
def calculate_sequence(m):
    _iter = 0
    _len = 0
    _sum = 0
    while True:
        _iter = int(str(_iter + m)[-1])
        _sum += _iter
        _len += 1
        if _iter == 0:
            break
 
        
    return _len, _sum
 
def seq_gen(m, cycles):
    _iter = 0
    while cycles > 0:
        _iter = int(str(_iter + m)[-1])
        cycles -= 1
        yield _iter
 
def process(n, m):
    seq_len, seq_sum = calculate_sequence(m)
    good_pages = n//m
    multiplier = seq_sum
    complete_sequences = good_pages//seq_len
    left_elements = good_pages%seq_len
 
    # total = complete_sequences * seq_sum + sum(x for x in seq_gen(m, left_elements))
    total = math.floor(good_pages/10) * sum(m*(i+1) % 10 for i in range(10)) + sum(m*(i+1) % 10 for i in range(good_pages%10))
    return total
 
 
datasets = int(input())
for _ in range(datasets):
    n, m = [int(x) for x in input().split(' ')]
    print(process(n, m))