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
t = int(input())
for i in range(t):
    n,m = map(int,input().split())
    arr = []
    sum = 0
    ans = 0
    nt = n//m
    if m %2 == 0:
        for i in range(5):
            arr.append((m*(i+1))%10)
            sum+=arr[i]
    else:
        for i in range (10):
            arr.append((m*(i+1))%10)
            sum += arr[i]

    if m%2 == 0:
        if nt < 5:
            for i in range(nt):
                ans+=arr[i]
        else:
            ans += (nt // 5)*sum
            if nt%5!= 0:
                for i in range(nt%5):
                    ans+= arr[i]
    else:
        if nt < 10:
            for i in range(nt):
                ans +=arr[i]
        else:
            ans += (nt // 10)*sum
            if nt%10 != 0:
                for i in range(nt%10):
                    ans+= arr[i]
    print(ans)