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.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.io.PrintWriter;
    import java.util.StringTokenizer;
    import java.util.Arrays;
     
    public class a{
        
        public static void main(String[] args)throws IOException{
	    br = new BufferedReader(new InputStreamReader(System.in));
	    PrintWriter out = new PrintWriter(System.out);
	    int n = nextInt();
	    for(int i = 0; i<n;i++){
		long a = nextLong();
		long b = nextLong();
		long t = a/b;
		b = b%10;
		long s = 0;
		int v[] = new int[10];
		int u = 0;
		for(int j = 0; j<10;j++){
		    v[j] =(int)(b*(j+1))%10;
		    s+=v[j];
		    if(v[j]==0){
			u =j+1;
			break;
		    }
		}
		s*=t/u;
		for(int j = 1; j<=t%u;j++){
		    s+=(j*b)%10;
		}
		out.println(s);
	    }
	    out.close();
	}
	
        static BufferedReader br;
        static StringTokenizer st = new StringTokenizer("");
        static String next()throws IOException{
	    while(!st.hasMoreTokens()){
		st = new StringTokenizer(br.readLine());
	    }
	    return st.nextToken();
        }
        static int nextInt()throws IOException{
	    return Integer.parseInt(next());
        }
	static long nextLong()throws IOException{
	    return Long.parseLong(next());
	}
    }
