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
def fun(i):
    freq = 2
    total= i%10
    while((i*freq)%10!=i%10):
        total = total+ (i*freq)%10
        freq+=1
        
    return (freq-1,total)


q= int(input())
for i in range(q):
        n,k = map(int,input().split())
        freq,total = fun(k) 
        temp = n//k

        ans = (temp//freq)*total
        remaining = temp%freq

        for j in range(1,remaining+1):
            ans  = ans+(j*k)%10

        print(ans)
       
