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
import java.util.*;
public class bookreading {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
Scanner sc=new Scanner(System.in);
int t=sc.nextInt();
sc.nextLine();
while(t>0)
{
long x=sc.nextLong();
long m=sc.nextLong();
long k=x/m;
long sum=0;
//System.out.println("k initial"+k);
long val=m%10;
int c=1;
//System.out.println("inside");
while(val != 0) {
    sum += val;
    val = (val + m) % 10;
    c++;
//System.out.println(val);
}
//System.out.println("------------     ");

// cout << m << " " << cyc << " " << s << endl;
long ans = (k / c) * sum;
k %= c;
//System.out.println(ans+" "+k);
for(long i=1;i<=k;i++)
{
	ans=ans+(i*m)%10;
}
System.out.println(ans);
t--;
}
}

}
