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
num = int(input())

i=0
# while(i<num):
#     arr=list(map(int,input().split()))
#     j=arr[1]
#     count=0;
#     while(j<=arr[0]):
#         d=j%10
#         count=count+d
#         j=j+arr[1]
#     i=i+1
#     print(count)

def engage(x):
    i=1
    count=0
    while(i<11):
        v=(x*i)%10
        count=count+v
        i=i+1
    return count

def extension(req,x):

    i=1
    sume=0
    while(i<x+1):
        sume=sume+((req*i)%10);
        i=i+1
    return sume



while(i<num):
    arr=list(map(int,input().split()))
    count=0
    count=engage(arr[1])

    r=arr[0]%arr[1]
    div=(arr[0]-r)//(arr[1])
    zero=div%10
    first=extension(arr[1],zero)
    second=div//10
    b=second*count + first
    print(b)
    i=i+1
