#include <bits/stdc++.h>

using namespace std;
using ll = long long;
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	int n;
	cin>>n;
	vector<ll>a(n);
	for(int i=0;i<n;i++) {
		cin>>a[i];
	}
	sort(rbegin(a), rend(a));
	ll sm=accumulate(begin(a),end(a),0ll);
	ll mask=0ll;
	if(sm == (1ll<<63ll)) mask |=(1ll<<63ll);
	for(ll i=0ll;i<=62ll;i++){
		ll up = (1ll<<(i+1));
		ll down = (1ll<<(i));
		ll loc=0ll;
		for(int j=0;j<n;j++) {
			if(loc + a[j] >= up) continue;
			loc+=a[j];
		}
		if(down <= loc) {
			mask|=loc;
			
			}
	}
	cout << mask << '\n';
	
	
	return 0;
	}