import strutils,sequtils
var
    N = stdin.readline.parseInt
    A = stdin.readline.split.map(parseInt)
    m,M : int
m = A[0]
M = A[0]
for a in A[1..high(A)]:
    (m, M) = (min([m + a,m - a,m * a,M * a]),max([M + a,M - a,M * a,m * a]))
echo M