#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int a, b, c;
  cin >> a >> b >> c;
  int a1 = min(a, min(c, b));
  int c1 = max(a, max(c, b));
  int b1 = a + b + c - a1 - c1;
  cout << max(0, c1 - b1 - a1 + 1);
}
