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