Tempuratures fixed :P

import sys
import math

n = int(input())  # the number of temperatures to analyse
closest_temp = 5527
closest_real_temp = 0
unsign_temp = 0
for i in input().split():
    # t: a temperature expressed as an integer ranging from -273 to 5526
    t = int(i)
    if t > 0 and closest_real_temp < 0:
        if -t == closest_real_temp:
            closest_real_temp = t
    else:

        if t < 0:
            unsign_temp = -t

        else:
            unsign_temp = t
        if unsign_temp < closest_temp:
            closest_temp = unsign_temp
            closest_real_temp = t
print(closest_real_temp)