n = int(input())
L = [int(input()) for i in range(n)]
minus = sorted([i for i in L if i <0])
plus = sorted([i for i in L if i>0],reverse = True)
zero = L.count(0)
S = 0
for i in range(0,len(plus),2):
try:
if plus[i]+plus[i+1] < plus[i]*plus[i+1]:
S += plus[i]*plus[i+1]
else:
S += plus[i] + plus[i+1]
except:
S += plus[i]
for i in range(0,len(minus),2):
try:
S += minus[i] * minus[i+1]
except:
if zero > 0:
zero -= 1
else:
S += minus[i]
print(S)