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 range(q):
    n,m = [int(j) for j in input().split()]
    if (m>n):
        print (0)
    elif (m==n):
        print (m%10)
    else:
        if (n<=(10*m)):
            const = n//m
            sum = 0
            for j in range(1,const+1):
                sum += ( (m*j)%10 )
            print (sum)
        else:
            sum = 0
            for j in range(1,11):
                sum += ( (m*j)%10 )
            const = n//m
            sum *= (const//10)
            for j in range(m*(10*(const//10)+1), n+1, m ):
                sum += (j%10)
            print (sum)





