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