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
for _ in range(int(input())):
    n,m=map(int,input().split())
    sum=0
    if n<m:
        sum=0
        print(sum)
    elif n==m:
        n=str(n)
        print(n[-1])
    else:
        n=n-n%m
        ans=n//m
        a=[]
        for i in range(1,11):
            a.append(i*m)
        if ans<=10:
            for i in range(0,ans):
                 z = str(a[i])
                 sum += (int(z[-1]))
            print(sum)
        else:
            rem = ans % 10
            div = (ans-rem)//10
            for i in range(0,len(a)):
                    z=str(a[i])
                    sum+=(int(z[-1])*div)
            for i in range(0,rem):
                z = str(a[i])
                sum += (int(z[-1]))
            print(sum)
        
