#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<queue>
#include<map>
#include<math.h>
#include<iomanip>
#include<set>
#include<numeric>
#include<cstring>
#include<cstdio>
#include<functional>
#include<bitset>
#include<limits.h>
#include<cassert>
#include<iterator>
#include<complex>
#include<stack>
using namespace std;
#define lint long long int
/*
vector<char>al(26);
al = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
vector<char>AL(26);
AL = {'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};
*/

int main() {
	vector<string>vec(4);
	getline(cin, vec.at(0));
	getline(cin, vec.at(1));
	lint Z = vec.at(1).size();
	lint cnt = 0;
	for (lint i = 0; i < Z; i++) {
		if (vec.at(1).at(i) == ' ') {
			cnt++;
		}
	}
	if (cnt) {
		cout << '"'<<"assert"<<'"' << endl;
	}
	else {
		getline(cin, vec.at(2));
		getline(cin, vec.at(3));
		vector<lint>veca(4);
		for (lint i = 0; i < 4; i++) {
			veca.at(i) = stoi(vec.at(i));
		}
		vector<lint>vecb(3);
		for (lint i = 0; i < 3; i++) {
			vecb.at(i) = veca.at(i + 1);
		}
		sort(vecb.begin(), vecb.end());
		vector<lint>vecc(3);
		vecc.at(0) = vecb.at(0) + vecb.at(1);
		vecc.at(1) = vecb.at(0) + vecb.at(2);
		vecc.at(2) = vecb.at(1) + vecb.at(2);
		sort(vecc.begin(), vecc.end());
		if (vecc.at(2) != vecc.at(1)) {
			cout << vecc.at(1) << endl;
		}
		else {
			cout << vecc.at(0) << endl;
		}
	}
}