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

I0 = lambda :map(int,input().split())
I1 = lambda :int(input())
I2 = lambda :list(map(int,input().split()))
#####################################################

def cal(j,t,n,m1):
        yy = t*m1
        x = (n-j)//yy
        return x
       

for i in range(I1()):
        n,m = I0()
        res=0
        num=[0]*10
        m1=m
        b = list()
        tol = 0
        while m <= n:
                if num[m%10] == 0:
                        num[m%10] = 1
                        b.append(m)
                        tol+=1
                        m+=m1
                else:
                        break
        
        
        for j in b:
                num[j%10]+=cal(j,tol,n,m1)
        #num[2]+=cal(12,10,n,m1)
        #print(b)
        #print(num)
        for j in range(10):
                res+=num[j]*j
        print(res)
        





