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
/*input
7
1 1
10 1
100 3
1024 14
998244353 1337
123 144
1234312817382646 13

*/




import java.math.*;
import java.io.*;
import java.util.*;
public class Main
{
    static class Reader 
    { 
        final private int BUFFER_SIZE = 1 << 16; 
        private DataInputStream din; 
        private byte[] buffer; 
        private int bufferPointer, bytesRead;
public Reader() 
        { 
            din = new DataInputStream(System.in); 
            buffer = new byte[BUFFER_SIZE]; 
            bufferPointer = bytesRead = 0; 
        }
public Reader(String file_name) throws IOException 
        { 
            din = new DataInputStream(new FileInputStream(file_name)); 
            buffer = new byte[BUFFER_SIZE]; 
            bufferPointer = bytesRead = 0; 
        }
public String readLine() throws IOException 
        { 
            byte[] buf = new byte[64]; // line length 
            int cnt = 0, c; 
            while ((c = read()) != -1) 
            { 
                if (c == '\n') 
                    break; 
                buf[cnt++] = (byte) c; 
            } 
            return new String(buf, 0, cnt); 
        }
public int nextInt() throws IOException 
        { 
            int ret = 0; 
            byte c = read(); 
            while (c <= ' ') 
                c = read(); 
            boolean neg = (c == '-'); 
            if (neg) 
                c = read(); 
            do
            { 
                ret = ret * 10 + c - '0'; 
            }  while ((c = read()) >= '0' && c <= '9');
if (neg) 
                return -ret; 
            return ret; 
        }
public long nextLong() throws IOException 
        { 
            long ret = 0; 
            byte c = read(); 
            while (c <= ' ') 
                c = read(); 
            boolean neg = (c == '-'); 
            if (neg) 
                c = read(); 
            do { 
                ret = ret * 10 + c - '0'; 
            } 
            while ((c = read()) >= '0' && c <= '9'); 
            if (neg) 
                return -ret; 
            return ret; 
        }
public double nextDouble() throws IOException 
        { 
            double ret = 0, div = 1; 
            byte c = read(); 
            while (c <= ' ') 
                c = read(); 
            boolean neg = (c == '-'); 
            if (neg) 
                c = read();
do { 
                ret = ret * 10 + c - '0'; 
            } 
            while ((c = read()) >= '0' && c <= '9');
if (c == '.') 
            { 
                while ((c = read()) >= '0' && c <= '9') 
                { 
                    ret += (c - '0') / (div *= 10); 
                } 
            }
if (neg) 
                return -ret; 
            return ret; 
        }
private void fillBuffer() throws IOException 
        { 
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
            if (bytesRead == -1) 
                buffer[0] = -1; 
        }
private byte read() throws IOException 
        { 
            if (bufferPointer == bytesRead) 
                fillBuffer(); 
            return buffer[bufferPointer++]; 
        }
public void close() throws IOException 
        { 
            if (din == null) 
                return; 
            din.close(); 
        } 
    } 




        
    static Reader sc=new Reader();
    static BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(System.out));

    public static void main(String args[])throws IOException
    {
        /*
         * For integer input: int n=inputInt();
         * For long input: long n=inputLong();
         * For double input: double n=inputDouble();
         * For String input: String s=inputString();
         * Logic goes here
         * For printing without space: print(a+""); where a is a variable of any datatype
         * For printing with space: printSp(a+""); where a is a variable of any datatype
         * For printing with new line: println(a+""); where a is a variable of any datatype
            Scanner in = new Scanner(System.in);
        //all four
         int[] dr = { 1, 0, -1, 0 };
         int[] dc = { 0, 1, 0, -1 };
         */
 
 		int t=inputInt();

 		while(t-->0)
 		{
 			long n=inputLong(),m=inputLong();

 			long[] a= new long[11];
 			if(n<m)
 			{
 				println(0+"");
 			}
 			else{
 			for(int j=1;j<=10;j++)
			{
				a[j] = a[j-1] + (j*m)%10;
			}
			long div=n/m;
			long temp=div%10;
 			long ans=(a[10]*(div/10));
 			ans+=a[(int)temp];
 			println(ans+"");
 			}


 			
 		}
      
    


  bw.flush();
  bw.close();

}

static long nCr(long n, long r) 
{ 
    long ans=1;
    if(r>n-r)
    {
    	r=n-r;
    }

    for(long i=1;i<=r;i++)
    {
    	ans*=(n-i+1);
    	ans/=i;

    }

    return ans;
} 
 

  




        public static int modulo(int x,int N)
        {
            return (x % N + N) %N;
        }
        public static long lcm(long a,long b)
        {    
            return a / gcd(a, b) * b;
        }
        public static long gcd(long a,long b)
        {
            if(b==0)
                return a;
            return gcd(b,a%b);
        }

     public static int inputInt()throws IOException
    {
        return sc.nextInt();
    }
    public static long inputLong()throws IOException
    {
        return sc.nextLong();
    }
    public static double inputDouble()throws IOException
    {
        return sc.nextDouble();
    }
    public static String inputString()throws IOException
    {
        return sc.readLine();
    }
    public static void print(String a)throws IOException
    {
        bw.write(a);
    }
    public static void printSp(String a)throws IOException
    {
        bw.write(a+" ");
    }
    public static void println(String a)throws IOException
    {
        bw.write(a+"\n");
    }
}