#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, c;
  cin >> a >> b >> c;
  int jum = a + b + c;
  int maks = max(max(a, b), c);
  int ans = maks - (jum - maks) + 1;
  if (ans < 1)
    cout << 0 << endl;
  else
    cout << ans << endl;
}
