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
import sys
input = sys.stdin.readline

Q = int(input())
Query = [list(map(int, input().split())) for _ in range(Q)]

for N, M in Query:
    used = set()
    loop = []
    c = 0
    while True:
        c = (c+M)%10
        if c in used:
            break
        loop.append(c)
        used.add(c)
    
    times = N//M
    L = len(loop)
    ans = sum(loop)*(times//L) + sum(loop[:times%L])
    print(ans)