#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 4000000000000000001



int main(){
	
	int n;
	cin>>n;
	
	vector<int> a(n);
	rep(i,n)cin>>a[i];
	
	if(n>=16){
		cout<<(1<<16)-1<<endl;
		return 0;
	}
	vector<int> dp(1<<16,0);
	dp[0] = 1;
	
	rep(i,n){
		vector<int> ndp(1<<16,0);
		rep(j,1<<16){
			if(dp[j]==0)continue;
			int t = a[i];
			rep(k,16){
				if(t&1)t ^= 1<<16;
				t>>=1;
				ndp[j|t] = 1;
			}
			
		}
		swap(dp,ndp);
	}
	for(int i=dp.size()-1;i>=0;i--){
		if(dp[i]){
			cout<<i<<endl;
			return 0;
		}
	}
	
	
	
	return 0;
}