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
//package codeforces;
import java.math.BigInteger;
import java.util.*;
public class code_583_C {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		int t=sc.nextInt();
		while(t>0) {
			t--;
			BigInteger n=sc.nextBigInteger();
			BigInteger m=sc.nextBigInteger();
			BigInteger q=n.divide(m);
			if(m.mod(new BigInteger("2")).equals(new BigInteger("0"))) {
				if(m.mod(new BigInteger("10")).equals(new BigInteger("0"))) {
					
					System.out.println(0);
				}
				else {
					BigInteger a= q.divide(new BigInteger("5"));
					BigInteger b=q.mod(new BigInteger("5"));
					BigInteger sum=a.multiply(new BigInteger("20"));
					BigInteger l=m.mod(new BigInteger("10"));
					
					for(int i=1;i<=Integer.parseInt(""+b);i++) {
						sum=sum.add(l.multiply(new BigInteger(Integer.toString(i))).mod(new BigInteger("10")));
					}
					System.out.println(sum);
				}
			}
			else {
				
				if(m.mod(new BigInteger("5")).equals(new BigInteger("0"))) {
					BigInteger a= q.divide(new BigInteger("10"));
					BigInteger b=q.mod(new BigInteger("10"));
					BigInteger sum=a.multiply(new BigInteger("25"));
					BigInteger l=new BigInteger("5");
					for(int i=1;i<=Integer.parseInt(""+b);i++) {
						sum=sum.add(l.multiply(new BigInteger(Integer.toString(i))).mod(new BigInteger("10")));
					}
					System.out.println(sum);
				}
				else {
					BigInteger a= q.divide(new BigInteger("10"));
					BigInteger b=q.mod(new BigInteger("10"));
					BigInteger sum=a.multiply(new BigInteger("45"));
					BigInteger l=m.mod(new BigInteger("10"));
					
					for(int i=1;i<=Integer.parseInt(""+b);i++) {
						sum=sum.add(l.multiply(new BigInteger(Integer.toString(i))).mod(new BigInteger("10")));
					}
					System.out.println(sum);
				}
			}
		}

	}

}
