#include <bits/stdc++.h>
using namespace std;
int main() {
  int a[3];
  while (1) {
    cin >> a[0] >> a[1] >> a[2];
    if (cin.eof()) break;
    sort(a, a + 3);
    if (a[2] < a[0] + a[1])
      cout << 0 << endl;
    else
      cout << a[2] - (a[0] + a[1]) + 1 << endl;
  }
}
