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