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,math,fractions,bisect
def fi():
    return int(sys.stdin.readline())

def fi2():
    return map(int, sys.stdin.readline().split())

def fi3():
    return sys.stdin.readline()

def fo(*args):
    for s in args:
        sys.stdout.write(str(s)+' ')
    sys.stdout.write('\n')
INF=10**9+7
sys.setrecursionlimit(INF)

#main
Q=fi()
for q in range(Q):
    n,m=fi2()
    f=n/m
    #print f
    l=m%10
    b=[1,2,3,4,5,6,7,8,9,0]
    S=[]
    s=0
    for i in b:
        s+=(i*l)%10
        S.append(s)
    #print f

    if f%10==0:
        fo(s*(f/10))
    else:
        fo(s*(f/10) +S[f%10-1])
        

        
        
        
    
    
    
            




    
            


    

        
    
    
        
        
        
    
    
    
            
            
            
            
    
                
    
        
    

        
        
    


    
    
            
                
            
            
        
    
    
        
    
    
    
            

    
    



    
        
            
    
        
