#include <bits/stdc++.h>
using namespace std;

int main()
{
	int N;
	cin >> N;
	cin.ignore( numeric_limits<streamsize>::max(), '\n' );
	vector<long long> A( N );
	for( int i = 0; i < N; i++ ) {
		string s;
		getline( cin, s );
		if( s == "" ) {
			cout << "\"assert\"" << endl;
			return 0;
		}
		sscanf( s.c_str(), "%lld", &A[i] );
	}

	vector<long long> b( N );
	for( int i = 0; i < N; i++ ) {
		b[i] = A[i] + A[(i + 1) % N];
	}
	sort( b.begin(), b.end() );
	long long ans = b[1];
	if( ans == b[2] ) ans = b[0];

	cout << ans << endl;
}