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.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
public class Solution
{
    static class comp implements Comparator<A>
    {
        public int compare(A a,A b)
        {
            return -(a.count-b.count);
        }
    }
    static class A{
        int index;
        int count;
        A(int index,int count)
        {
            this.index=index;
            this.count=count;
        }
    }
	public static void main (String[] args)
	{
            FastReader s1 = new FastReader();
            StringBuilder sb = new StringBuilder();
            int t=s1.I();
            while(t--!=0)
            {
                long n=s1.L();
                long m=s1.L();
                long no=n/m;
                HashSet<Long> hs = new HashSet<>();
                hs.add(m%10);
                long j=2;
                long demo=m;
                long sum=m%10;
                long digit=0;
                ArrayList<Long> ai = new ArrayList<>();
                ai.add(m%10);
                while(true)
                {
                    demo = m*j;
                    digit=(demo%10);
                    if(!hs.add(digit))
                    {
                        break;
                    }
                    j++;
                    ai.add(digit);
                    sum+=digit;
                }
          //      System.out.println(hs);
            //    System.out.println(n+" "+m+" jjjjjj "+demo+" "+hs.size()+" "+sum);
                int f=hs.size();
                long fac=no/f;
                sum=sum*fac;
                fac=no%f;
                for(int i=0;i<fac;i++)
                {
                    sum+=ai.get(i);
                }
                sb.append(sum).append("\n");
            }
            System.out.println(sb);
	}
        static int binary(int left,int right,int ar[],int no)
        {
             int mid=(left+right)/2;
             if(Math.abs(right-left)<=1)
             {
                 if(no>=ar[right])
                 {
                     return right+1;
                 }
                 else if(no<ar[left])
                 {
                     return left;
                 }
                 else
                 {
                      return left+1;
                 }
             }
             if(ar[mid]>no)
             {
                 right=mid-1;
                 return binary(left, right, ar, no);
             }
             else{
                 left=mid;
                 return binary(left, right, ar, no);
                         }
        }
	static 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 I() 
        { 
            return Integer.parseInt(next()); 
        } 
  
        long L() 
        { 
            return Long.parseLong(next()); 
        } 
  
        double D() 
        { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() 
        { 
            String str = ""; 
            try
            { 
                str = br.readLine(); 
            } 
            catch (IOException e) 
            { 
                e.printStackTrace(); 
            } 
            return str; 
        } 
    }
    static int gcd(int a,int b)
		{
		    if(a%b==0)
		    return b;
		    return gcd(b,a%b);
		}
	static float power(float x, int y) 
    { 
        float temp; 
        if( y == 0) 
            return 1; 
        temp = power(x, y/2);  
          
        if (y%2 == 0) 
            return temp*temp; 
        else
        { 
            if(y > 0) 
                return x * temp * temp; 
            else
                return (temp * temp) / x; 
        } 
    } 
    static long pow(int a,int b)
    {
        long result=1;
        if(b==0)
        return 1;
        long x=a;
        while(b>0)
        {
            if(b%2!=0)
            result*=x;
            
            x=x*x;
            b=b/2;
        }
        return result;
    }
    
    static ArrayList<Integer> sieveOfEratosthenes(int n) 
    { 
        ArrayList<Integer> arr=new ArrayList<Integer>();
        boolean prime[] = new boolean[n+1]; 
        for(int i=2;i<n;i++) 
            prime[i] = true; 
          
        for(int p = 2; p*p <=n; p++) 
        { 
            if(prime[p] == true) 
            { 
                arr.add(p);
                for(int i = p*p; i <= n; i += p) 
                    prime[i] = false; 
            } 
        } 
        return arr;
    } 
}