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
import math
import bisect
import atexit
import io
import heapq
from collections import defaultdict, Counter
import itertools
MOD = int(1e9+7)


# n = map(int, raw_input().split())
# input = map(int, raw_input().split())



def main():
    ka = map(int, raw_input().split())[0]
    while ka:
        ka -= 1
        n, m = map(int, raw_input().split())
        c = [m%10]
        last = m%10
        while True:
            if (last+m)%10 in c:
                break
            c.append((last+m)%10)
            last = (last+m)%10
        ti = n/m
        sm = sum(c)
        ans = sm*(ti/len(c)) + sum(c[:ti%len(c)])
        print ans

main()
