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
q=int(input())
for i in xrange(q):
    n,m=map(int,raw_input().split())
    d={}
    l=[m%10]
    i=m+m
    while(1):
        if i%m==0:
            x=i%10
            if l[0]==x:
                break
            else:
                l.append(x)
        i+=m
    if n==m:
        print n%10
    elif len(l)==0:
        print 0
    else:
        a=n/m
        b=a/len(l)
        ans=sum(l)
        ans=ans*b
        c=a%len(l)
        ans+=sum(l[:c])
        print ans