#include <bits/stdc++.h>
using namespace std;
const long long MAX = 1e6, MOD = 1e9 + 7;
long long a[3];
int32_t main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> a[0] >> a[1] >> a[2];
  sort(a, a + 3);
  if (a[0] + a[1] <= a[2])
    cout << a[2] - (a[0] + a[1]) + 1;
  else
    cout << "0";
  return 0;
}
