import sys num = sys.stdin.readline().strip() sign = 1 if num[0] == "-": sign = -1 n = float(num[1:]) else: n = float(num) if n == 0: print(0.0 * sign) if n == 1: print(1.0 * sign) if n > 1: left, right = 1, n if 0 < n < 1: left, right = n, 1 while left < right: mid = (left + right) / 2 ...