n=int(input())
a=list(map(int,input().split()))
A=sum(a)
L=5000*(n if n<=142 else 2)
q=[0]*L
q[0]=1
for v in a:
  for i in reversed(range(L)):
    if i+v<L:
      q[i+v]+=q[i]
      q[i+v]=min(q[i+v],2)
for i in range(1,A//2+A%2):
  if i<L and q[i]==2:
    print(A-i*2)
    exit()
print(-1)