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 bisect
import decimal
from decimal import Decimal
import os
from collections import Counter
import bisect
from collections import defaultdict
import math
import random
import heapq 
from math import sqrt
import sys
from functools import reduce, cmp_to_key
from collections import deque
import threading
from itertools import combinations
from io import BytesIO, IOBase
from itertools import accumulate

# sys.setrecursionlimit(200000)
# mod = 10**9+7
# mod = 998244353
decimal.getcontext().prec = 46

def primeFactors(n): 
    prime = set()
    while n % 2 == 0: 
        prime.add(2)
        n = n//2
    for i in range(3,int(math.sqrt(n))+1,2): 
        while n % i== 0: 
            prime.add(i)
            n = n//i 
    if n > 2: 
        prime.add(n)
    return list(prime)
    
def getFactors(n) : 
    factors = []
    i = 1
    while i <= math.sqrt(n): 
        if (n % i == 0) : 
            if (n // i == i) : 
                factors.append(i)
            else : 
                factors.append(i)
                factors.append(n//i)
        i = i + 1
    return factors
    
def modefiedSieve(): 
    mx=10**7+1
    sieve=[-1]*mx
    for i in range(2,mx):
        if sieve[i]==-1:
            sieve[i]=i
            for j in range(i*i,mx,i):
                if sieve[j]==-1:
                    sieve[j]=i
    return sieve
    
def SieveOfEratosthenes(n): 
    prime = [True for i in range(n+1)] 
    p = 2
    while (p * p <= n): 
        if (prime[p] == True): 
            for i in range(p * p, n+1, p): 
                prime[i] = False
        p += 1
    num = []
    for p in range(2, n+1): 
        if prime[p]: 
            num.append(p)
    return num

def lcm(a,b):
    return (a*b)//math.gcd(a,b)

def sort_dict(key_value):
    return sorted(key_value.items(), key = lambda kv:(kv[1], kv[0]), reverse=True)

def list_input():
    return list(map(int,input().split()))
    
def num_input():
    return map(int,input().split())
    
def string_list():
    return list(input())
    
def decimalToBinary(n):  
    return bin(n).replace("0b", "")  
    
def binaryToDecimal(n): 
    return int(n,2) 
    
def DFS(n,s,adj):              
    visited = [False for i in range(n+1)]  
    stack = [] 
    stack.append(s)  
  
    while (len(stack)):  
        s = stack[-1]  
        stack.pop() 
  
        if (not visited[s]):  
            visited[s] = True 
            
        for node in adj[s]:  
            if (not visited[node]):  
                stack.append(node)  
        
def maxSubArraySum(a,size): 
    maxint = 10**10
    max_so_far = -maxint - 1
    max_ending_here = 0
       
    for i in range(0, size): 
        max_ending_here = max_ending_here + a[i] 
        if (max_so_far < max_ending_here): 
            max_so_far = max_ending_here 
  
        if max_ending_here < 0: 
            max_ending_here = 0   
    return max_so_far 
    
def lis(arr): 
    n = len(arr) 
    lis = [1]*n 
    for i in range (1 , n): 
        for j in range(0 , i): 
            if arr[i] >= arr[j] and lis[i]< lis[j] + 1 : 
                lis[i] = lis[j]+1
    maximum = 0
    for i in range(n): 
        maximum = max(maximum , lis[i]) 
  
    return maximum 
        
def solve():
    n,m = num_input()
    if m%10 == 0:
        print(0)
        return
    n = (n//m)*m
    if n == 0:
        print(0)
        return
    ans = 0
    if m%2 == 0:
        upper = (n//(m*10))
        if upper == 0:
            c = 1
            while m*c <= n:
                ans += (m*c)%10
                c += 1
        else:
            ans = 40*upper
            c = ((n//(m*10))*(m*10))//m+1
            while m*c <= n:
                ans += (m*c)%10
                c += 1
    elif m%5 == 0:
        upper = n//m
        ans = 5*(upper//2)
        if upper%2 != 0:
            ans += 5
    else:
        upper = (n//(m*10))
        if upper == 0:
            c = 1
            while m*c <= n:
                ans += (m*c)%10
                c += 1
        else:
            ans = 45*upper
            c = ((n//(m*10))*(m*10))//m+1
            while m*c <= n:
                ans += (m*c)%10
                c += 1
    print(ans)
    
t = 1
t = int(input())
for _ in range(t):
    solve()


    
    
    
    
