import sys, time, random
from collections import deque, Counter, defaultdict
def debug(*x):print('debug:',*x, file=sys.stderr)
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
inf = 2 ** 61 - 1
mod = 998244353

n = ii()

a = li()
ans = 0
if max(a) > 0:
    ans += 2 * max(a)
    
if min(a) < 0:
    ans -= 2 * min(a)
    
print(ans)