1213_C. Book Reading
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
```python
q = int(input())

for i in range(q):
    n, m = input().split(" ")

    n = int(n)
    m = int(m)

    if n == m:
        print(m%10)
        continue

    inicial = m

    aux = (m%10)
    m += inicial

    while (m%10) != (inicial%10) and m <= n:
        aux += (m%10)
        m += inicial
    
    m = m-inicial
    
    mult = int(n/m)
    resultado = mult*aux
    m = m*mult
    
    m += inicial

    while m <= n:
        resultado += (m%10)
        m += inicial
    
    print(resultado)
   			 			 			 								  		 	
```