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
''''
import sys
sys .stdin = open("input.txt")
'''
T = int(input())

for t in range (0,T):
    L = list(map(int,input().split()))
    t = (L[0])
    M = (L[1])
    m = M*10
    g = t//m
    b = 0
    s = 0
    r = t%m
    a = 0
    m = M*10
    gx=0
    stp=[]
    
    for n in range(M, m,M):
        pag= str(n)
        p = len(pag)
        cifra = int (pag[p-1])
        a = a + cifra
        bt= a*g
    
    for z in range(M,r+1,M):
        pag = str (z)
        p = len(pag)
        cifra = int(pag[p-1])
        b = b + cifra
        
    ris = b
    f=bt+ris
    print(f)






        
        
    
    
    



















