#include <bits/stdc++.h>
#include <atcoder/all>
typedef long long int ll;
using namespace std;
typedef pair<ll, ll> P;
using namespace atcoder;
template<typename T> using min_priority_queue = priority_queue<T, vector<T>, greater<T>>;
#define USE998244353
#ifdef USE998244353
const ll MOD = 998244353;
using mint = modint998244353;
#else
const ll MOD = 1000000007;
using mint = modint1000000007;
#endif

#pragma region //使いがち
const int MAX = 2000001;
long long fac[MAX], finv[MAX], inv[MAX];
void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }
}
long long COM(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}
ll pow_ll(ll x, ll n) {
    if (n == 0) return 1;
    if (n % 2) {
        return pow_ll(x, n - 1) * x;
    }
    else {
        ll tmp = pow_ll(x, n / 2);
        return tmp * tmp;
    }
}
// floor(a^(1/k))
ll floor_root(ll a, ll k) {
    assert(a >= 0);
    assert(k >= 1);
    if (a == 0) return 0;
    if (k == 1) return a;
    // 大体の値
    ll x = (ll)pow(a, 1.0 / k);
    // 増やす
    while ((pow_ll(x + 1, k)) <= a) {
        x++;
    }
    // 減らす
    while ((pow_ll(x, k)) > a) {
        x--;
    }
    return x;
}
ll keta(ll num, ll arity) {
    ll ret = 0;
    while (num) {
        num /= arity;
        ret++;
    }
    return ret;
}
// k進数で見た時のi桁目の数を返す (一番下は0桁目)
ll keta_num(ll num, ll i, ll k) {
    return (num / pow_ll(k, i)) % k;
}
ll ceil(ll n, ll m) {
    // n > 0, m > 0
    ll ret = n / m;
    if (n % m) ret++;
    return ret;
}
void compress(vector<ll>& v) {
    // [3 5 5 6 1 1 10 1] -> [1 2 2 3 0 0 4 0] 
    vector<ll> u = v;
    sort(u.begin(), u.end());
    u.erase(unique(u.begin(),u.end()),u.end());
    map<ll, ll> mp;
    for (int i = 0; i < u.size(); i++) {
        mp[u[i]] = i;
    }
    for (int i = 0; i < v.size(); i++) {
        v[i] = mp[v[i]];
    }
}
vector<pair<ll, ll> > prime_factorize(ll N) {
    vector<pair<ll, ll> > res;
    for (ll a = 2; a * a <= N; ++a) {
        if (N % a != 0) continue;
        ll ex = 0; // 指数

        // 割れる限り割り続ける
        while (N % a == 0) {
            ++ex;
            N /= a;
        }

        // その結果を push
        res.push_back({a, ex});
    }

    // 最後に残った数について
    if (N != 1) res.push_back({N, 1});
    return res;
}
#pragma endregion

// 1以上n以下について素数かどうかのリストを返す
vector<bool> is_prime_list(int n) {
    vector<bool> is_prime(n + 1, true);
    is_prime[0] = false;
    is_prime[1] = false;
    for (int i = 2; i * i <= n; i++) {
        if (!is_prime[i]) continue;
        for (int j = i * 2; j <= n; j += i) {
            is_prime[j] = false;
        }
    }
    return is_prime;
}

int main() {
    int n;
    cin >> n;
    vector<ll> a(n);
    ll sum = 0;
    for (int i = 0; i < n; i++) {
        cin >> a[i];
        sum += a[i];
    }
    vector<ll> dp(850001, 0);
    dp[0] = 1;
    for (int i = 0; i < n; i++) {
        vector<ll> dp2(850001, 0);
        for (int j = 0; j < 850001; j++) {
            if (j + a[i] < 850001) {
                dp2[j + a[i]] += dp[j];
            }
        }
        for (int j = 0; j < 850001; j++) {
            dp[j] += dp2[j];
        }
    }
    for (ll i = 1; i < 850001; i++) {
        if ((dp[i] >= 2) && (i * 2 < sum)) {
            cout << sum - 2 * i << endl;
            exit(0);
        }
    }
    cout << -1 << endl;
    return 0;
}