#include <bits/stdc++.h>
using namespace std;
int main() {
  int arr[3];
  cin >> arr[0] >> arr[1] >> arr[2];
  sort(arr, arr + 3);
  cout << ((arr[0] + arr[1] > arr[2]) ? 0 : (arr[2] - arr[0] - arr[1] + 1))
       << "\n";
}
