import java.util.*;

public class Pythagoras{
	public static void main(String [] args) throws Exception {
		Scanner scanner = new Scanner(System.in);

		System.out.print("Enter the (integer) length of the side of the square: ");
		int side = scanner.nextInt();

		double diagonal = Math.sqrt(2) * side;

		System.out.println("The length of the diagonal of a square with a side of length " + side + " is " + diagonal);
	}
}