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

def get_array(): return list(map(int, sys.stdin.readline().strip().split()))
def read():  return int(input())
def reads(): return map(int, sys.stdin.readline().strip().split())
def input(): return sys.stdin.readline().strip() #strip() avoid reading '\n'

def solve(n, m):
    loop = []
    cyc = n // m
    t = m % 10
    while len(loop) == 0 or loop[0] != t:
        loop.append(t)
        t = (t + m % 10) % 10
    s = 0
    for x in loop:
        s = s + x
    res = cyc // len(loop) * s
    cyc = cyc % len(loop)
    while cyc:
        res = res + loop[cyc - 1]
        cyc = cyc - 1
    return res
        

cas = read()
while cas:
    n, m = reads()
    print(solve(n, m))
    cas = cas - 1
