#define _USE_MATH_DEFINES

#include <iostream>
#include <iomanip>

#include <algorithm>
#include <cmath>

#include <string>
#include <list>
#include <queue>
#include <vector>
#include <complex>
#include <set>

/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
/////////
typedef long long LL;
typedef long double LD;
/////////
using namespace::std;
/////////

int main(void){
    std::cin.tie(0); 
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed;//
    //cout << setprecision(6);//

	int A,B,S;
	cin>>A>>B>>S;
	int ansA,ansB;
	if( abs(S-A) <= abs(S-B) ){
		ansA = abs(S-A) + S;
		P( ansA );
	}else{
		if(S==1){
			ansB = A;
		}else{
			ansB = abs(S-B) + min(abs(S-A),abs(S-1)) + A;
		}
		if(A==0) ansB+=2;//S>S-1
		P( ansB );
	}
    return 0;
}