N = int(input())
C = list(map(int, input().split()))
ans = float("inf")
if C[0] >= 0:
    ans = min(ans, C[-1] * 2)
elif C[-1] <= 0:
    ans = min(ans, abs(C[0]) * 2)
else:
    ans = min(ans, abs(C[0]) * 2 + abs(C[-1]) * 2)
print(ans)