#include <bits/stdc++.h>
using namespace std;

int w,a,b;

int main()
{
	cin >> w >> a >> b;
	if(a + w > b && abs(a + w - b) <= w)
	{
		cout << 0 << endl;
	}
	else if(a + w < b)
	{
		cout << abs(a + w - b) << endl;
	}
	else 
	{
		cout << a - b - w << endl;
	}
	return 0;
}