import java.util.Stack;

public class Program {

	public static void decToBinString(int number) {
		String bin = "";
		while (number != 0) {
			bin += number % 2;
			number /= 2;
		}
		// reverse
		for(int i = bin.length() - 1; i >= 0; i--) {
			System.out.print(bin.charAt(i));
		}
	}
	
	public static void decToBinStack(int number) {
		Stack<Integer> bin = new Stack<Integer>();
		while (number != 0) {
			bin.push(number % 2);
			number /= 2;
		}
		
		while (!bin.empty()) {
			System.out.print(bin.pop());
		}
	}
	
	public static int binToDec(int bin) {
		int dec = 0;
		int power = 0;
		while (bin != 0) {
			dec += (bin % 10) * Math.pow(2, power);
			power++;
			bin /= 10;
		}
		return dec;
	}
	
	public static void main(String[] args) {
		while (true) {
			System.out.println("1. BIN -> DEC");
			System.out.println("2. DEC -> BIN");
			System.out.println("3. EXIT");
		}
		
	}
}