#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using ull=unsigned long long;
using pll=pair<ll,ll>;
using tll=tuple<ll,ll,ll>;
using ld=long double;
const ll INF=(1ll<<60);
#define rep(i,n) for (ll i=0;i<(ll)(n);i++)
#define replr(i,l,r) for (ll i=(ll)(l);i<(ll)(r);i++)
#define all(v) v.begin(),v.end()
#define len(v) ((ll)v.size())
template<class T> inline bool chmin(T &a,T b){
    if(a>b){
        a=b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T &a,T b){
    if(a<b){
        a=b;
        return true;
    }
    return false;
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    ll n;
    cin >> n;
    vector<ll> a(n);
    ll sum=0;
    rep(i,n){
        cin >> a[i];
        sum+=a[i];
    }
    ll x=1,c=n;
    while(c<=5000*x&&x<n){
        c*=n-x;
        c/=x+1;
        x++;
    }
    ll sz=5000*x+1;
    vector<vector<ll>> dp(n+1,vector<ll>(sz,0));
    dp[0][0]=1;
    rep(i,n){
        rep(j,sz){
            dp[i+1][j]=min(2ll,dp[i+1][j]+dp[i][j]);
            if(j+a[i]<sz) dp[i+1][j+a[i]]=min(2ll,dp[i+1][j+a[i]]+dp[i][j]);
        }
    }
    ll t=INF;
    rep(i,(sum+1)/2){
        if(2<=dp[n][i]) chmin(t,i);
    }
    if(t==INF){
        cout << "-1\n";
    }else{
        cout << sum-2*t << '\n';
    }
}