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 re
# inf = float("inf")
#sys.setrecursionlimit(1000000)



# from cmath import sqrt
# from collections import deque, Counter, OrderedDict,defaultdict
# from heapq import nsmallest, nlargest, heapify,heappop ,heappush, heapreplace
# from math import ceil,floor,log,sqrt,factorial,pow,pi,gcd,log10,atan,tan
# from bisect import bisect_left,bisect_right
# import numpy as np

def get_array(): return list(map(int , sys.stdin.readline().strip().split()))
def get_ints(): return map(int, sys.stdin.readline().strip().split())
def input(): return sys.stdin.readline().strip()

T=int(input())
while T>0:
    n,m=get_ints()
    if m%10==0:
        print(0)
        T-=1
        continue
    elif m%5==0:
        x=25
    elif m&1:
        x=45
    elif not m&1:
        x=40
    div=n//m
    tens=div//10
    total=tens*x
    rem=div%10
    for i in range(rem):
        total+=((m*(i+1))%10)
    print(total)
    T-=1
#
# for i in range(1,20):
#     total=0
#     for j in range(1,11):
#         total+=(i*j)%10
#     print(i,"= ",total)