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
# 求在[1,n]区间，所有能被m整除的数字的末尾数之和
def cal(num):
    seq = []
    for i in range(1,11):
        seq.append(int(str(num * i)[-1]))
    return seq
#print(cal(7))
test = int(input())
for i in range(test):
    seq = input().split()
    page = int(seq[0])
    m = int(seq[1][-1])
    onespan = cal(m)
    turn = page//int(seq[1]) #符合条件的页数一共有turn
    whole = (turn//10) * sum(onespan)
    #print("lalal",turn,turn%10)
    other = sum(onespan[:turn%10])
    print(whole+other)

