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.*;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class a{ 
     static int[] count,count1;
     static Node[] arr;
     static char[] ch,ch1;
     static long[] darr;
     static long[][] mat;
     static long x;
     static long maxl;
     static double dec;
     static String s;
     // static long minl;
     static int mx = (int)1e6;
     static long mod = 998244353l;
     // static int minl = -1;
     static long n;
     // static int n,n1,n2;
     static long a,g;
     static long b;
     static long c;
     static long d;
     static long y;
     static long m;
     static long k;
     static int q;
     static String[] str,str1;
     static Set<Character> set,set1;
     static List<Long> list;
     static Map<Long,Integer> map;
     static StringBuilder sb;

     public static long solve(){

        long num = 0;
        long sum = 0;
        while(num < n) {
            num += m;
            sum += num%10;
            if(num%10 == 0)
                break;
        } 
        // System.out.println(num+" "+sum);
        sum = ((n/num) * sum);
        // System.out.println(sum);
        long k = 0;
        // System.out.println(n%num);
        while(k <= (n%num)) {
            sum += k%10;
            k += m;
        }    

        return sum; 

     }

     public static void main(String[] args) {

            FastScanner sc = new FastScanner();
            // Scanner sc = new Scanner(System.in);
            int t = sc.nextInt();
            // int t = 1;
            while(t > 0){
                 // set = new HashSet<>();
                 // map = new HashMap<>();
                
                // x = sc.nextLong();
                // y = sc.nextLong();
                
                // a = sc.nextLong();
                // b = sc.nextLong();
                // g = sc.nextLong();
                // n = sc.nextInt();
                // n1 = sc.nextInt();
                // n1 = sc.nextInt();

                
                // c = sc.nextLong();
                // d = sc.nextLong();
                // k = sc.nextLong();
                // d = sc.nextLong();
                n = sc.nextLong();
                // x = sc.nextLong();
                // ch = sc.next().toCharArray();
                // ch1 = sc.next().toCharArray();
                // s = sc.next();

                 // long x = sc.nextLong();

                
                // k = sc.nextLong();
                // dec = sc.nextDouble();
                // n = sc.nextInt();
                m = sc.nextLong();
                // x = sc.nextLong();
                 
                // arr = new Node[n];
                // for(int i = 0; i < n ; i++){
                //     arr[i] = new Node(sc.nextInt(),i+1);
                // }
                // // set = new HashSet<>();
                // for(int i = 0 ; i < n ; i++)
                //     set.add(sc.next().charAt(0));
                
                // n1 = sc.nextInt();
                //  darr = new long[n1];
                //  for(int i = 0; i < n1 ; i++){
                //      darr[i] = sc.nextLong();
                //  }

                // mat = new long[n][n1];

                // for(int i = 0 ; i < n ; i++){
                //     for(int j = 0 ; j < n1 ; j++){
                //         mat[i][j] = sc.nextLong();
                //     }
                // }


                // System.out.println(solve()?"YES":"NO");
                 // solve();
                 System.out.println(solve());
                 // sb = new StringBuilder();
                 // sb.append(str);

                 t -= 1;
            }

     }

    public static int log(long n){

         if(n == 0 || n == 1)
             return 0;

         if(n == 2)
             return 1;

         double num = Math.log(n);
         double den = Math.log(2);

         if(den == 0)
             return 0;

         return (int)(num/den);
     }

     public static long gcd(long a,long b){

        if(b%a == 0)
            return a;

        return gcd(b%a,a);

     }

     // public static void swap(int i,int j){
     //     long temp = arr[j];
     //     arr[j] = arr[i];
     //     arr[i] = temp;
     // } 

    static final Random random=new Random();
    
    static void ruffleSort(long[] a) {
        int n=a.length;//shuffle, then sort 
        for (int i=0; i<n; i++) {
            int oi=random.nextInt(n);
            long temp=a[oi];
            a[oi]=a[i]; a[i]=temp;
        }
        Arrays.sort(a);
    }

    static class Node{
        int first;
        int second;
        Node(int f,int s){
            this.first = f;
            this.second = s;
        }
    }

     static class FastScanner {

                BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
                StringTokenizer st=new StringTokenizer("");
                String next() {
                        while (!st.hasMoreTokens())
                                try {
                                        st=new StringTokenizer(br.readLine());
                                } catch (IOException e) {
                                        e.printStackTrace();
                                }
                        return st.nextToken();
                }
                
                int nextInt() {
                        return Integer.parseInt(next());
                }
                int[] readArray(int n) {
                        int[] a=new int[n];
                        for (int i=0; i<n; i++) a[i]=nextInt();
                        return a;
                }
                long nextLong() {
                        return Long.parseLong(next());
                }
        }

}