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