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(raw_input())
ans = []
while q:
    q-=1
    aa = []
    n,m = map(int, raw_input().split())
    sum = 0
    div = n/m
    cur = 0
    size = 0
    smallsum = 0
    tmp = 0
    cur+=m%10
    aa.append(cur)
    cur+=m
    cur%=10
    while(cur!=aa[0]):
        smallsum+=cur
        aa.append(cur)
        cur+=m
        cur%=10
        size+=1
    smallsum+=cur
    size+=1
    sum+=smallsum * (div/size)
    while(tmp < div%size):
        sum+=aa[tmp]
        tmp+=1
    ans.append(sum)

for an in ans:
    print an