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

int main(){
	int A, B, S;
	cin >> A >> B >> S;

	int AS = abs(A - S);
	int BS = abs(B - S);

	if(AS <= BS){
		cout << AS + S << endl;
	} else if(A == 0) {
		cout << BS + S + 1 << endl;
	} else {
		cout << min(BS + AS + A, BS + S - 1 + A - 1 + 1) << endl;
	}

	return 0;
}