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
queries = int(input())
def books(n, m) :
    l = []
    i = 1
    j = 0
    s = 0
    if(n < m) : s = 0
    if(n <= 100000) :
        while(i <= n and j <= n) :
            j = m*i
            if(j > n) : break
            else : l.append((m*i) % 10)
        
            i += 1
        s = sum(l)
    else :
        for i in range(1, 1000):
            k = (m*i) % 10
            if k not in l :
                l.append(k)
        
        s = sum(l) * (n // m // len(l))
        o = (n // m) - len(l) * (n // m // len(l))
        for i in range(0, o) : 
            s += l[i]
    return s

for i in range(queries) :
    nm = list(input().split(" "))
    n = int(nm[0])
    m = int(nm[1])
    print(books(n, m))

