import java.util.Scanner;

public class BinarySearchSqrt {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		System.out.println("Enter a number: ");

		double number = sc.nextInt();// what they want to find sqrt

		// range that we know the answer is in
		double low = 0;
		double high = number;

		// begin guessing
		for (int trial = 0; trial < 100; trial++) {
			double guess = (low + high) / 2;// guess in the middle

			if (guess * guess < number) {
				// guess too low
				low = guess;
			} else if (guess * guess > number) {
				// guess too high
				high = guess;
			} else {
				// perfect guess
				System.out.println(guess);
				return;
			}
		}

		// could not get perfect guess
		System.out.println(low);
	}

}