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
'''


7
1 1
10 1
100 3
1024 14
998244353 1337
123 144
1234312817382646 13


'''

l=[[1,2,3,4,5,6,7,8,9,0],[2,4,6,8,0],[3,6,9,2,5,8,1,4,7,0],[4,8,2,6,0],[5,0],[6,2,8,4,0],[7,4,1,8,5,2,9,6,3,0],[8,6,4,2,0],[9,8,7,6,5,4,3,2,1,0],[0]]
n=int(input())
for i in range(0,n):
    p=input().rstrip().split(' ')
    A=int(p[0])
    B=int(p[1])
    if A<B:
        print(0)
    elif A==B:
        H=list(p[0])
        H.reverse();
        print(H[0])
    else:
        H=list(p[1])
        H.reverse();
        C=A//B;
        D=len(l[int(H[0])-1])
        E=C//D;
        F=C%D;
        S=0;
        for j in range(0,len(l[int(H[0])-1])):
            S+=(E*l[int(H[0])-1][j])
        for j in range(0,len(l[int(H[0])-1])):
            if F>0:
                S+=(l[int(H[0])-1][j])
                F-=1;
        print(S)