import  java.io.*;                          
 class	 Triangle{
	int a,b,c;
	public void set(int i,int j, int k){
		a=i;
		b=j;
		c=k;
	}
	public boolean judge(){
		if (a+b>c && a+c>b && b+c>a)
			return true;
		return false;
	}
	public double getArea(){
		double s=(a+b+c)/2;
		return  Math.sqrt(s*(s-a)*(s-b)*(s-c));
	}
	
	public double getPerimeter(){
		return a+b+c;
	}	
}


public class TestExcTriangle{
	public static void main(String[] args){
		Reader ir = new InputStreamReader(System.in);
		BufferedReader r = new BufferedReader(ir);
		String sc="";
		int intA=0,intB=0,intC=0;
		System.out.print("輸入第1條: ");
		try{
			sc = r.readLine();
		}catch (IOException e){}
		try{
			intA=Integer.parseInt(sc);
		}catch (NumberFormatException e){
			System.out.println("輸入的數據不是整數");
		}
	
		System.out.print("輸入第2條邊: ");
		try{
			sc = r.readLine();
		}catch (IOException e){}
		try{
			intB=Integer.parseInt(sc);
		}catch (NumberFormatException e){
			System.out.println("輸入的數據不是整數");
		}
		
		System.out.print("輸入第3條邊:");
		try{
			sc = r.readLine();
		}catch (IOException e){}
		try{
			intC=Integer.parseInt(sc);
		}catch (NumberFormatException e){
			System.out.println("輸入的數據不是整數");
		}
		
		
		Triangle b = new Triangle();
		if (b.judge());
		b.set(intA,intB,intC);	
		if (b.judge()==false){
			System.out.println("判斷不合法");
			}
		System.out.println("周長 ＝ "+b.getPerimeter());
		System.out.println("面積 ＝ "+b.getArea());
		
	}
}