// DoubleSum.java

class DoubleSum {
	
	public static void main(String[] args) {
		// declare three double variables
		double x, y, sum;
		
		// read in the values for x and y
		System.out.print("Enter a double value: ");
		x = readDouble();
		System.out.print("Enter another double value: ");
		y = readDouble();
		
		// compute their sum
		sum = x + y;
		
		// print out their sum
		System.out.print("Their sum is: ");
		System.out.println(sum);
	}
	
	///////////////////////////////////
	// readString, readInt, readDouble
	///////////////////////////////////
	
	public static String readString() {
		java.io.InputStreamReader isr = new java.io.InputStreamReader(System.in);
		java.io.BufferedReader d = new java.io.BufferedReader(isr);
		try { return d.readLine(); } catch (Exception e) { return "error"; }
	}
	public static int readInt() { return Integer.parseInt(readString()); }
	public static double readDouble() {
		return Double.valueOf(readString()).doubleValue();
	}
}