# Arup Guha
# 2/17/2026
# Solution to Kattis Problem Bootstrapping Number
# Used to illustrate real-valued binary search.
# https://open.kattis.com/problems/bootstrappingnumber

# Get the input.
n = float(input())

# Based on the limits to their input.
low = 1
high = 10

# Fixed number of iterations.
for loop in range(100):

    # Guess.
    mid = (low+high)/2

    # Too small here answer is at least equal to mid.
    if mid**mid < n:
        low = mid

    # Too big here, answer is mid or less.
    else:
        high = mid

# Ta da!
print(low)