#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod=1e9+7;

ll N;
ll A[5];
ll B[5];

int main(){ 

cin.tie(0);
ios::sync_with_stdio(false);

string n,s1,s2,s3;

getline(cin,n);
getline(cin,s1); 
if(s1.size()>2){
	cout<<"assert"<<endl;
	return 0;
}
getline(cin,s2);
getline(cin,s3);

A[0]=stoll(s1);
A[1]=stoll(s2);
A[2]=stoll(s3);

B[0]=A[0]+A[1];
B[1]=A[1]+A[2];
B[2]=A[2]+A[0];

sort(B,B+3);

if(B[1]!=B[2]) cout<<B[1]<<endl;
else cout<<B[0]<<endl;


}