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 bisect import *
from collections import *
from itertools import *
import functools
import sys
import math
from decimal import *
from copy import *
getcontext().prec = 30
MAX = sys.maxsize
MAXN = 10**5+10
MOD = 10**9+7
def isprime(n):
    n = abs(int(n))
    if n < 2:
        return False
    if n == 2: 
        return True    
    if not n & 1: 
        return False
    for x in range(3, int(n**0.5) + 1, 2):
        if n % x == 0:
            return False
    return True

def mhd(a,b):
    return abs(a[0]-b[0])+abs(b[1]-a[1])

def charIN(x= ' '):
    return(sys.stdin.readline().strip().split(x))

def arrIN(x = ' '):
    return list(map(int,sys.stdin.readline().strip().split(x)))

def eld(x,y):
    a = y[0]-x[0]
    b = x[1]-y[1]
    return (a*a+b*b)**0.5

def lgcd(a):
    g = a[0]
    for i in range(1,len(a)):
        g = math.gcd(g,a[i])
    return g

def ms(a):
    msf = -MAX
    meh = 0
    st = en = be = 0
    for i in range(len(a)):
        meh+=a[i]
        if msf<meh:
            msf = meh
            st = be
            en = i
        if meh<0:
            meh = 0
            be = i+1
    return msf,st,en

def ncr(n,r):
    num=den=1
    for i in range(r):
        num = (num*(n-i))%MOD
        den = (den*(i+1))%MOD

    return (num*(pow(den,MOD-2,MOD)))%MOD



def flush():
    return sys.stdout.flush()


def fac(n):
    ans = 1
    for i in range(1,n+1):
        ans*=i
        ans%=MOD
    return ans

'''*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*'''
x = [[0 for i in range(10)] for j in range(10)]
for i in range(10):
    for j in range(1,10):
        x[i][j]+=x[i][j-1]+int(str(i*j)[-1])

for _ in range(int(input())):
    n,m = arrIN()
    if n<m or m%10==0:
        print(0)
    else:
        a=n//m
        t = m*a
        b = a%10
        ans = ((a-b)//10)*x[int(str(m)[-1])][9]+x[int(str(m)[-1])][b]
        print(ans)

