// EmptyProgram.java
// <your name here>

// Start with this shell when writing a program from scratch.

class EmptyProgram {
	
	public static void main(String[] args) {

		// your code here!
		
	}

	///////////////////////////////////////////////
	// readString, readInt, readDouble, readBoolean
	///////////////////////////////////////////////
	
	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() {
		while (true) {
			try { return Integer.parseInt(readString()); }
			catch (Exception e) {
				System.out.print("Error. Try again. Please enter an integer: "); 
			}
		}
	}

	public static double readDouble() {
		while (true) {
			try { return Double.parseDouble(readString()); }
			catch (Exception e) {
				System.out.print("Error. Try again. Please enter a double: "); 
			}
		}
	}

	public static boolean readBoolean() {
		while (true) {
			String reply = readString().toLowerCase();
			if (reply.equals("true")) return true;
			if (reply.equals("false")) return false;
			System.out.print("Error. Try again. Please enter 'true' or 'false': ");
		}
	}
}