#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 1000000000000000001


int main(){
	
	int n;
	cin>>n;
	vector<int> a(n);
	rep(i,n)cin>>a[i];
	int maxi;
	if(n>=101)maxi = 5000;
	else maxi = 5000 * n;
	vector dp(maxi*2+1,Inf32);

	rep(i,n){
		vector ndp = dp;
		rep(j,maxi*2+1){
			if(j-a[i]>=0)ndp[j-a[i]] = min(ndp[j-a[i]],dp[j] + a[i]);
			if(j+a[i]<=maxi*2)ndp[j+a[i]] = min(ndp[j+a[i]],dp[j]+ a[i]);
			if(maxi+a[i]<=maxi*2)ndp[maxi+a[i]] = min(ndp[maxi+a[i]],a[i]);
			if(maxi-a[i]>=0)ndp[maxi-a[i]] = min(ndp[maxi-a[i]],a[i]);
		}
		swap(dp,ndp);
	}
	int ans = dp[maxi];
	if(ans==Inf32)ans = -1;
	else{
		int sum = 0;
		rep(i,n)sum += a[i];
		ans = sum-ans;
		if(ans==0)ans = -1;
	}
	cout<<ans<<endl;
    return 0;
}