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

int dp[3000][3000][2];

int main() {
	int A, B, S;
	cin >> A >> B >> S;
	int ans;
	if (abs(S - A) <= abs(S - B) || S == 1){
		ans = abs(S - A) + S;
	}
	else{
		ans = abs(S - B) + (S - 1) + A;
	}
	cout << ans << endl;
}