from pulp import *

N = int(input())
R = list(map(int, input().split()))
prob = LpProblem(name="yukicoder_2918", sense=LpMinimize)
X = [LpVariable(name="X"+str(i), cat=LpBinary) for i in range(N)]
Y = [LpVariable(name="Y"+str(i), cat=LpBinary) for i in range(N)]
M = 10 ** 8
zp = LpVariable(name="Zp", lowBound=0, cat=LpInteger)
zm = LpVariable(name="Zm", lowBound=0, cat=LpInteger)
z = LpVariable(name="Z", cat=LpBinary)
prob += zp <= z * M
prob += zm <= (1 - z) * M
prob += zp + zm
constraint = 0
for i in range(N):
    constraint += (X[i] - Y[i]) * R[i]
    prob += X[i] + Y[i] <= 1
prob += zp - zm == constraint
prob += lpSum(X) >= 1
prob += lpSum(Y) >= 1

status = prob.solve(PULP_CBC_CMD(msg = False))
print(int(value(prob.objective)))