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
#!/usr/bin/env python
# coding: utf-8

# In[ ]:


import math
q=int(input())
while(q>0):
    q-=1  
    n_m=input()
    n_m=n_m.split()
    n=int(n_m[0])
    m=int(n_m[1])
    i=1
    digits=[]
    summation=0
    summation_temp=0
    
    while(True):
        temp=str(i*m)
        temp=int(temp[-1])
        if temp in digits or m*i>n:
            break
        else:
            digits.append(temp)
        i+=1
    if len(digits)==0:
        print(summation)
        continue
    for i in digits:
        summation_temp=summation_temp+i
    x1=(n//m)
    summation=summation_temp*(x1//len(digits))
    
    for i in range(x1-len(digits)*(x1//len(digits))):
        summation=summation+digits[i]
    
    print(summation) 

