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
# -*- coding: utf-8 -*-
"""
Created on Mon Jul 27 06:43:22 2020

@author: Dark Soul
"""

t=int(input(''))
arr=[]
for i in range(t):
    arr.append(list(map(int, input().split())))
for i in arr:
    n=i[0]
    m=i[1]
    s=0
    for j in range(1,11):
        s+=(m*j)%10
    tot=n//(m*10)
    if tot*m*10==n:
        print(s*tot)
    else:
        s=s*tot
        rem=n-(tot*m*10)
        left=rem//m
        for j in range(1,left+1):
            s+=(m*j)%10
        print(s)