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, itertools, math

def ia():
  return [int(i) for i in sys.stdin.readline().strip().split(" ")]

def ii():
  return int(sys.stdin.readline().strip())

def istr():
  return sys.stdin.readline().strip()

###

for _ in range(ii()):
  n, m = ia()
  D = []
  for i in range(100022222200):
    p = i * m
    if i > 0 and p % 10 == 0:
      break
    D.append(p%10)

  rep = n//len(D)//m
  ans = sum(D)*rep

  for i in range(rep*len(D), n+1):
    p = i * m
    if p > n:
      break
    ans += p % 10

  print(ans)

