UVA - 10195 - The Knights Of The Round Table

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.StringTokenizer;
import javax.crypto.Mac;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuffer sb = new StringBuffer("");
        String m="";
        while((m=br.readLine())!=null){
            StringTokenizer st=new StringTokenizer(m);
            double x=Double.parseDouble(st.nextToken());
            double y=Double.parseDouble(st.nextToken());
            double z=Double.parseDouble(st.nextToken());
            double ans=rad(x, y, z);
            String f=String.format("The radius of the round table is: %.3f\n",ans);
            sb.append(f);
        }
        System.out.print(sb);
    }
   
    static double rad(double x,double y,double z){
        if(x==0 ||y==0 ||z==0)
            return 0;
        double halfP=(x+y+z)/2;
        return Math.sqrt((halfP-x)*(halfP-y)*(halfP-z)/halfP);
    }
}