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
t=int(input())
d=[[]] * 10
d[1]=[ 1, 2, 3, 4,5 ,6 ,7, 8,9, 0]
d[2]=[ 2, 4, 6, 8, 0]
d[3]=[3, 6, 9, 2, 5, 8, 1, 4, 7, 0]
d[4]=[4, 8, 2, 6, 0]
d[5]=[5, 0]
d[6]=[6, 2, 8, 4, 0]
d[7]=[7, 4, 1, 8, 5, 2, 9, 6, 3, 0]
d[8]=[8, 6, 4, 2, 0]
d[9]=[9, 8, 7, 6, 5, 4, 3, 2, 1 , 0]
dd=[10, 5, 10, 5, 2, 5, 10, 5, 10]

for i in range(t):
    n, m=map(int, input().split())
    if m<=n:
        a=n//m
        b=m%10
        c=a//dd[b-1]
        cc=a%dd[b-1]

        print(c*sum(d[b])+sum(d[b][:cc]))
    else:
        print(0)