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())

for ii in range(t):
    n, m = [int(x) for x in input().split(' ')]
    d = n // m
    #print('%s) d: %s' % (ii+1, d))
    dlist = [int(str(i*m)[-1]) for i in range(1, min(d, 11)+1)]
    #dlist = [int(str(i*m)[-1]) for i in range(1, d+1)]
    if d < 10:
        print(sum(dlist))
    else:
        x = dlist[0]
        #print(dlist)
        res = x
        end_index = 0
        for i, a in enumerate(dlist[1:]):
            if x != a:
                res += a
            else:
                end_index = i + 1
                break
        #print('end_index: %s' % end_index)
        if end_index:
            cycles = d // end_index
            s = res * cycles
            for i in range(d % end_index):
                s += dlist[i]
            #print(dlist)
            print(s)
        else:
            print(sum(dlist))
