import sys, time, random
from collections import deque, Counter, defaultdict
import logging
from logging import debug, error, info, warning
logging.basicConfig(level=logging.DEBUG)
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
inf = 2 ** 61 - 1
mod = 998244353

n = ii()
a = li()
a.sort()
dp = [[[-inf] * 7001 for _ in range(n + 1)] for _ in range(2)]

dp[0][0][0] = 0
for i in range(n):
    for j in range(7001):
        dp[0][i + 1][j] = max(dp[0][i + 1][j], dp[0][i][j] + a[i])
        dp[1][i + 1][j] = max(dp[1][i + 1][j], dp[1][i][j] + a[i])
        dp[1][i + 1][abs(j - a[i])] = max(dp[1][i + 1][abs(j - a[i])], dp[1][i][j])
        dp[1][i + 1][abs(j - a[i])] = max(dp[1][i + 1][abs(j - a[i])], dp[0][i][j])
        if j + a[i] <= 7000:
            dp[1][i + 1][j + a[i]] = max(dp[1][i + 1][j + a[i]], dp[1][i][j])
            dp[1][i + 1][j + a[i]] = max(dp[1][i + 1][j + a[i]], dp[0][i][j])

print(-1 if dp[1][n][0] <= 0 else dp[1][n][0])