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

N = int(input())

vstup=[0 for i in range(N)]
rozdelene=[ 0 for i in range(N)]
n=[0 for i in range(N)]
m=[0 for i in range(N)]
v=[0 for i in range(N)]
a=[0 for i in range(10)]

for i in range(N):
    vstup[i]=raw_input()
    rozdelene[i]=vstup[i].split(' ')

for i in range(N):
    n[i]=int(rozdelene[i][0])
    m[i]=int(rozdelene[i][1])

for i in range(N):
    if m[i]>n[i]:
        v[i]=0
    elif m[i]==n[i]:
        v[i]=n[i] % 10
    else:
        kolik = n[i] // m[i]
        desitek = kolik // 10
        zbytek = kolik % 10
        v[i]=0
        soucet = 0
        for j in range(10):
            a[j]=((j*m[i]) % 10)
            soucet = soucet + a[j]
        neco = 0
        for j in range(1,zbytek+1):
            neco=neco+a[j]
        v[i] = (soucet*desitek)+neco
    print(v[i])