#include <bits/stdc++.h>
using namespace std;
const int inf = 1e9 + 3;
const long long Linf = 1e18;
int main() {
  ios_base::sync_with_stdio(false);
  int x[3];
  cin >> x[0] >> x[1] >> x[2];
  sort(x, x + 3);
  int ans = (x[2] >= x[0] + x[1] ? x[2] - x[1] - x[0] + 1 : 0);
  cout << ans << '\n';
  return 0;
}
