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
n=int(input())
for x in range(n):
    page,div=list(map(int,input().split()))
    initial=1
    value=0
    count=0
    dic={}
    dic[0]=0
    while True:
        current=div*initial
        value+=int(str(current)[-1])
        dic[initial]=value
        initial+=1
        count+=1
        if str(current)[-1]=="0":
            break
    if current<page:
        dam=page//current
        value*=int(dam) 
        lam=page-(current*dam)
        init=int(lam//div)
        value+=dic[init]
        print(value)
    else:
        if div>page:
            print(0)
        else:
            initial=1
            value=5-5
            while True:
                current=div*initial
                value+=int(str(current)[-1])
                dic[initial]=value
                initial+=1
                count+=1
                if div*initial>page:
                    break
            print(value)

            
            
        