/* -*- coding: utf-8 -*-
 *
 * 851.cc:  No.851 テストケース - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int N = 3;
const int K = N * (N - 1) / 2;
const int LEN = 256;

/* typedef */

typedef long long ll;

/* global variables */

char s[LEN];
ll as[N], bs[K];

/* subroutines */

/* main */

int main() {
  fgets(s, LEN, stdin);
  fgets(s, LEN, stdin);

  if (index(s, ' ')) {
    puts("\"assert\"");
    return 0;
  }

  as[0] = atol(s);
  for (int i = 1; i < N; i++) scanf("%lld", as + i);

  for (int i = 0, k = 0; i < N; i++)
    for (int j = i + 1; j < N; j++) bs[k++] = as[i] + as[j];
  sort(bs, bs + K);
  int k = unique(bs, bs + K) - bs;

  printf("%lld\n", bs[k - 2]);
  return 0;
}