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.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;
import java.util.Scanner;
import java.math.BigInteger;

public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int q = sc.nextInt();
    int sums[] = {0,45,40,45,40,25,40,45,40,45};
    int nums[][] = {
      {0,0,0,0,0,0,0,0,0,0},
      {0,1,3,6,10,15,21,28,36,45},
      {0,2,6,12,20,20,22,26,32,40},
      {0,3,9,18,20,25,33,34,38,45},
      {0,4,12,14,20,20,24,32,34,40},
      {0,5,5,10,10,15,15,20,20,25},
      {0,6,8,16,20,20,26,28,36,40},
      {0,7,11,12,20,25,27,36,42,45},
      {0,8,14,18,20,20,28,34,38,40},
      {0,9,17,24,30,35,39,42,44,45}
    };
    while(sc.hasNext()){
      BigInteger n = sc.nextBigInteger();
      BigInteger m = sc.nextBigInteger();
      BigInteger val = n.divide(m);
      // System.out.println(val);
      BigInteger ans = BigInteger.ZERO;
      n = val.mod(BigInteger.valueOf(10));
      m = m.mod(BigInteger.valueOf(10));
      n = BigInteger.valueOf(nums[m.intValue()][n.intValue()]);
      // System.out.println(n);
      ans = ans.add(n);
      val = val.divide(BigInteger.valueOf(10));
      val = val.multiply(BigInteger.valueOf(sums[m.intValue()]));
      // System.out.println(val);
      ans = ans.add(val);
      System.out.println(ans);
    }
  }
}
