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 random
input = sys.stdin.readline

t =int(input())
for _ in range(t):

    n,m = list(map(int,input().split()))
    
    n = n//m
    
    #n=10q+r
    q = n//10
    r = n%10
    
    
    #10 following integers always have the same sum%10
    sum_10 = sum([m*i%10 for i in range(0,10)]) 
    
    #10q
    ans = q*sum_10
    
    #+r
    for i in range(r+1):
        ans+= m*i%10
        
    print(ans)