#include <bits/stdc++.h>
using namespace std;
int max(int A[], int size) {
  int i, max = -1;
  for (i = 0; i < size; i++) {
    if (A[i] > max) max = A[i];
  }
  return max;
}
int main() {
  int n, L[100001], i, s = 0;
  cin >> n;
  for (i = 0; i < n; i++) {
    cin >> L[i];
    s += L[i];
  }
  cout << 2 * max(L, n) - s + 1 << "\n";
  return 0;
}
