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())
    if n < m:
        print(0)
        continue
    elif m % 10 == 0:
        print(0)
    else:
        d = m % 10
        f = n // m
        a = 0
        if d % 2 == 0:
            k = f // 5
            k1 = f % 5
            a += k * 20
            for i in range(1, k1 + 1):
                a += (d * i) % 10
            print(a)
        elif d % 2 == 1 and d != 5:
            k = f // 10
            k1 = f % 10
            a += k * 45
            for i in range(1, k1 + 1):
                a += (d * i) % 10
            print(a)
        else:
            k = f // 2
            k1 = f % 2
            a += k * 5
            for i in range(1, k1 + 1):
                a += (d * i) % 10
            print(a)




