#include <bits/stdc++.h>
using namespace std;
int main() {
  int w, a, b;
  cin >> w >> a >> b;
  if (a + w < b) {
    cout << b - (a + w) << endl;
  } else if (a > b + w) {
    cout << a - (b + w) << endl;
  } else {
    cout << 0 << endl;
  }
  return 0;
}
