#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <math.h>
#include <map>

using namespace std;

int main(){
	
	long a,b,c;
	cin >> a >> b >> c;
	long mid=max(a,c);
	long mi=min(a,c);
	long cost=min((b-mid),(mid-mi));
	cout << cost << endl;
	return 0;
}