#include <bits/stdc++.h>
using namespace std;
double pi = acos(-1);
long long power(long long a, long long b) {
  long long p_res = 1;
  while (b > 0) {
    if (b % 2 == 1) {
      p_res *= a;
      b--;
    }
    a *= a;
    b /= 2;
  }
  return p_res;
}
int n;
vector<long long> vec;
long long l1, l2;
long long ans;
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    long long val;
    cin >> val;
    vec.push_back(val);
  }
  sort(vec.begin(), vec.end());
  int let = vec.size();
  l2 = vec[let - 1];
  l1 = vec[let - 2];
  for (int i = 0; i < let - 2; i++) {
    if (l1 <= l2)
      l1 += vec[i];
    else
      l2 += vec[i];
  }
  if (l1 == l2)
    cout << 1;
  else {
    if (l1 > l2) swap(l1, l2);
    cout << l2 - l1 + 1;
  }
  return 0;
}
