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())

for _ in range(q):
    n, m = list(map(int, input().split()))
    repeat = n // m
    lastDigit = m % 10
    curLastDigit = lastDigit

    ct = 0
    ans = 0
    while ct < repeat and ct < 10:
        ans += curLastDigit
        curLastDigit = (lastDigit + curLastDigit) % 10
        ct += 1

    if ct < repeat:
        ans *= repeat // 10

        repeat %= 10
        ct = 0
        curLastDigit = lastDigit
        while ct < repeat:
            ans += curLastDigit
            curLastDigit = (lastDigit + curLastDigit) % 10
            ct += 1

    print(ans)
