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
for t in range(int(input())):
    n,m=map(int,input().split())
    x=m%10
    c=n//m
    z=0
    if x==0:
        print(0)
    elif x==1:
        v=c//10
        v=v*45
        y=c%10
        f=x
        for i in range(1,y+1):
            z=z+f%10
            f=f+x
        print(v+z)
    elif x==2:
        v=c//5
        v=v*20
        y=c%5
        f=x
        for i in range(1,y+1):
            z=z+f%10
            f=f+x
        print(v+z)
    elif x==3:
        v=c//10
        v=v*45
        y=c%10
        f=x
        for i in range(1,y+1):
            z=z+f%10
            f=f+x
        print(v+z)
    elif x==4:
        v=c//5
        v=v*20
        y=c%5
        f=x
        for i in range(1,y+1):
            z=z+f%10
            f=f+x
        print(v+z)
    elif x==5:
        v=c//2
        v=v*5
        if c%2!=0:
            v=v+5
        print(v)
    elif x==6:
        v=c//5
        v=v*20
        y=c%5
        f=x
        for i in range(1,y+1):
            z=z+f%10
            f=f+x
        print(v+z)
    elif x==7:
        v=c//10
        v=v*45
        y=c%10
        f=x
        for i in range(1,y+1):
            z=z+f%10
            f=f+x
        print(v+z)
    elif x==8:
        v=c//5
        v=v*20
        y=c%5
        f=x
        for i in range(1,y+1):
            z=z+f%10
            f=f+x
        print(v+z)
    else:
        v=c//10
        v=v*45
        y=c%10
        f=x
        for i in range(1,y+1):
            z=z+f%10
            f=f+x
        print(v+z)