// Arup Guha
// 3/9/2024
// Solution to Kattis Problem: Bootstrapping Number

import java.util.*;

public class bootstrappingnumber {

	public static void main(String[] args) {
	
		Scanner stdin = new Scanner(System.in);
		double target = stdin.nextDouble();
		
		// Note: 10 to the 10th is 10,000,000,000 so the answer is no more than 10.
		//       also 1 to the 1 is 1...
		double low = 1, high = 10;
		
		// Run the binary search.
		for (int i=0; i<100; i++) {
		
			double mid = (low+high)/2;
			
			// mid is too small, update low.
			if (Math.pow(mid,mid) < target)
				low = mid;
			
			// mid is too big, update high.
			else
				high = mid;
		}
		
		// Ta da!
		System.out.println(low);
	}
}