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(raw_input())
for t_itr in xrange(t):
    n, m = map(int,raw_input().split())
    d = {}
    s = []
    if m > n:
        print 0
    else:
        st = 0
        i = 0
        while i< n+1:
            v = i%10
            e = d.get(v,0)
            if e == 0:
                st += 1
                d[v] = 1
            else:
                break                
            i = i + m
        k = n/(st*m)
        ans = 0
        i = 1
        while i<st+1:
           v = m*(k*st + i)
           if v <= n:
               ans += v%10
           else:break
           i = i + 1
        for i in d:
           ans += i*k
        print ans
       
            