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
#Eu já resolvi esse problema no semestre passado.
#Conforme conversado com o professor é permitido reenviar problemas já resolvidos.
#Link de quando o fiz: https://vjudge.net/contest/324788#problem/D

mat = [[],[10,45,1,2,3,4,5,6,7,8,9,0],[5,20,2,4,6,8,0],[10,45,3,6,9,2,5,8,1,4,7,0],[5,20,4,8,2,6,0,],[2,5,5,0],[5,20,6,2,8,4,0],[10,45,7,4,1,8,5,2,9,6,3,0],[5,20,8,6,4,2,0],[10,45,9,8,7,6,5,4,3,2,1,0]]

q = int(input())
for _ in range(q):
    n, m = map(int, input().split())
    soma = 0
    j = m%10
    if(j>0):
        soma = (n//(mat[j][0]*m))*mat[j][1]
        k = (n%(mat[j][0]*m))//m
        for i in range(k):
            soma+=mat[j][i+2]
            
    print(soma)
		   	  	  		   		  	 		  	  		