import java.util.*;
public class Tim_so_chinh_phuong {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		int a=sc.nextInt();
		int t=(int)Math.sqrt(a);
		System.out.println(t);
	}

}
