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
from math import *
from sys import *
from collections import defaultdict
M=10**9+7
def pow(a,b):
    res=1
    while b>0:
        if b&1:
            res*=a
        a*=a
        b>>=1
    return res
def powmod(a,b,m):
    res=1
    while b>0:
        if b&1:
            res=((res*a)%m)
        a*=a
        b>>=1
    return res
def inv(a,m):
    return powmod(a,m-2,m)

def factor(n):
    potentional_p = 3
    itog_list = {}
    if n % 2 == 0:
        itog_list[2] = 0
    while n % 2 == 0:
        n = n // 2
        itog_list[2] += 1
    while n - 1:
        if potentional_p > (n**0.5):
            if n in itog_list:
                itog_list[n] += 1
            else:
                itog_list[n] = 1
            return itog_list
        while n % potentional_p == 0:
            n = n // potentional_p
            if potentional_p in itog_list:
                itog_list[potentional_p] += 1
            else:
                itog_list[potentional_p] = 1
        potentional_p += 2
    return itog_list
def meth(m):
    if m==1:
        return [i for i in range(1,10)]+[0]
    if m==2:
        return [2,4,6,8,0]
    if m==3:
        return [3,6,9,2,5,8,1,4,7,0]
    if m==4:
        return [4,8,2,6,0]
    if m==5:
        return [5,0]
    if m==6:
        return [6,2,8,4,0]
    if m==7:
        return [7,4,1,8,5,2,9,6,3,0]
    if m==8:
        return [8,6,4,2,0]
    if m==9:
        return [9,8,7,6,5,4,3,2,1,0]
    if m==0:
        return [0]

t=int(input())
for _ in range(t):
    n,m=list(map(int,stdin.readline().split()))
    dif=meth(int(str(m)[-1]))
    val=int(n//m)
    ln=len(dif)
    res=(val//ln)*sum(dif)
    val-=(val//ln)*ln
    res+=sum(dif[:val])
    print(res)
