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 her who keeps the fire kindling in me...  //
                //                                                //
                ////////////////////////////////////////////////////


                import java.io.BufferedReader;
                import java.io.BufferedWriter;
                import java.io.FileOutputStream;
                import java.io.IOException; 
                import java.io.InputStreamReader;
                import java.io.OutputStream;
                import java.io.OutputStreamWriter;
                import java.io.PrintWriter;
                // import java.util.Scanner;
                // import java.util.Arrays;
                // import java.util.ArrayList;
                // import java.util.Collections; 
                // import java.util.StringTokenizer;
                import java.util.*;
                import java.lang.Math;
                import java.awt.Point;                            

                import java.awt.geom.*;
                
                public class Solution{
                
                    public static void main(String args[]){
                        try{
                            FastReader s = new FastReader();
                            BufferedWriter w = new BufferedWriter(new OutputStreamWriter(System.out));
                            int i, j, k, x, y, t, key, size, poster, minglob, minloc, beg, end, begl, endr, ld;
                            long ans, f, ansmin, n, m, q, r, sum1;//, sum2;
                            boolean flag;
                
                            long arr[][] = new long[10][11];
                            // for(i=0; i<10; i++)
                            //     for(j=1; j<=10; j++)
                            //         arr[i][j] = (long)((i*j)%10) + arr[i][j-1];
                            
                            t = s.nextInt();
                            for(; t>0; t--){
                
                            
                            n = s.nextLong();
                            m = s.nextLong();
                            
                            sum1=0;
                            for(i=1; i<=10; i++)
                                sum1+=((i*m)%10);
                            
                            //ld = (int)m%10;
                            ans = 0l;
                            n = n/m;
                            q = n/10;
                            r = n%10;
                            for(i=1; i<=r; i++)
                                ans+=((((long)i)*m)%10);
                            
                            ans+=(sum1*q);
                            //ans = arr[ld][10]*q + arr[ld][(int)r];
                            
                            w.write(ans+"\n");}
                            w.close();
                        }catch(Exception e){
                            e.printStackTrace();
                        }
                    }
                }
                                
                                
                //========================================### FAST IO ###=========================================//
                class FastReader 
                { 
                    BufferedReader br; 
                    StringTokenizer st; 
                
                    public FastReader() 
                    { 
                        br = new BufferedReader(new
                                    InputStreamReader(System.in)); 
                    } 
                
                    String next() 
                    { 
                        while (st == null || !st.hasMoreElements()) 
                        { 
                            try
                            { 
                                st = new StringTokenizer(br.readLine()); 
                            } 
                            catch (IOException  e) 
                            { 
                                e.printStackTrace(); 
                            } 
                        } 
                        return st.nextToken(); 
                    } 
                
                    int nextInt() 
                    { 
                        return Integer.parseInt(next()); 
                    } 
                
                    long nextLong() 
                    { 
                        return Long.parseLong(next()); 
                    } 
                
                    Double nextDouble() 
                    { 
                        return Double.parseDouble(next());
                    } 
                
                    String nextLine() 
                    { 
                        String str = ""; 
                        try
                        { 
                            str = br.readLine(); 
                        } 
                        catch (IOException e) 
                        { 
                            e.printStackTrace(); 
                        } 
                        return str;
                    } 
                }
                    //====================================================================================================//