#include <atcoder/all>
#include <bits/stdc++.h>
#define rep(i, a, b) for (ll i = (ll)(a); i < (ll)(b); i++)
using namespace atcoder;
using namespace std;

typedef long long ll;

int main() {
    int n;
    cin >> n;
    vector<int> a(n);
    rep(i, 0, n) cin >> a[i];
    int max_t, max_a = *max_element(a.begin(), a.end());
    int sum_a = accumulate(a.begin(), a.end(), 0);
    if (n <= 20)
        max_t = max_a * n + 10;
    else if (n <= 200)
        max_t = max_a * 10 + 10;
    else
        max_t = max_a * 2 + 10;
    int dp[n + 1][max_t + 1];
    rep(i, 0, n + 1) rep(j, 0, max_t + 1) dp[i][j] = 0;
    dp[0][0] = 1;
    rep(i, 0, n) {
        for (int j = max_t; j >= 0; j--) {
            dp[i + 1][j] += dp[i][j];
            if (j + a[i] <= max_t)
                dp[i + 1][j + a[i]] += dp[i][j];
        }
    }
    int mn = 1e9;
    rep(i, 0, max_t + 1) {
        if (dp[n][i] >= 2) {
            mn = i;
            break;
        }
    }
    int ans = sum_a - mn - mn;
    if (ans <= 0)
        ans = -1;
    cout << ans << endl;
}