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

#define REP(i, n) for (int i = (int)(0); i < (int)(n); ++i)
#define REPS(i, n) for (int i = (int)(1); i <= (int)(n); ++i)
#define RREP(i, n) for (int i = ((int)(n)-1); i >= 0; i--)
#define RREPS(i, n) for (int i = ((int)(n)); i > 0; i--)
#define IREP(i, m, n) for (int i = (int)(m); i < (int)(n); ++i)
#define IREPS(i, m, n) for (int i = (int)(m); i <= (int)(n); ++i)
#define FOR(e, c) for (auto &e : c)
#define SORT(v, n) sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define RVISORT(v) sort(v.begin(), v.end(), greater<int>());
#define ALL(v) v.begin(), v.end()
#define MP(n, m) make_pair(n, m);

using VI = vector<int>;
using VVI = vector<VI>;
using PII = pair<int, int>;
using ll = long long;
using ul = unsigned long;

typedef long long ll;

template<class T, class C> void chmax(T& a, C b){ a>b?:a=b; }
template<class T, class C> void chmin(T& a, C b){ a<b?:a=b; }

const int mod=1e9+7;

void printv(VI& v){
  REP(i,v.size()) cout << v[i] << " ";
  cout << endl;
}

int vtotal(VI& v){
  int total=0;
  REP(i,v.size()) total+=v[i];
  return total;
}

int main()
{
  cin.tie( 0 );
  ios::sync_with_stdio( false );

  string n;
	getline(cin,n);
  int num=stoi(n);

  vector<ll> v;
  REP(i,num){
    string s;
    getline(cin,s);
    if(s.find(" ")!= std::string::npos){
      cout<<"\"assert\""<<endl;
      return 0;
    }
    v.push_back(stoll(s));
  }

  vector<ll> v2;
  v2.push_back(v[0]+v[1]);
  v2.push_back(v[2]+v[1]);
  v2.push_back(v[0]+v[2]);
  VSORT(v2);
  
  if(v2[1]==v2[2])cout<<v2[0]<<endl;
  else cout<<v2[1]<<endl;
  

  return 0;
}