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())
    ms = str(m)[-1]
    lda = []
    if ms == "0":
        lda = [0,0]
    if ms == "1":
        lda = [i for i in range(1,10)]+[0]
    if ms == "2":
        lda = [2,4,6,8,0]
    if ms == "3":
        lda = [3,6,9,2,5,8,1,4,7,0]
    if ms == "4":
        lda = [4,8,2,6,0]
    if ms == "5":
        lda = [5,0]
    if ms == "6":
        lda = [6,2,8,4,0]
    if ms == "7":
        lda = [7,4,1,8,5,2,9,6,3,0]
    if ms == "8":
        lda = [8,6,4,2,0]
    if ms == "9":
        lda = [9,8,7,6,5,4,3,2,1,0]

    multiples = n // m
    per = len(lda)
    a, b = multiples//per, multiples % per
    print(sum(lda)*a + sum(lda[:(b)]))