#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <cstring>

typedef long long ll;
using namespace std;

const int mod = 1000000007;
const int INF = (int)1e9;
const ll LLINF = (ll)2e18;
const double PI = 3.1415926536;

const int SIZE = 1000;

int main(){
    int a,b,s,ans;
    int d_a,d_b;
    
    scanf("%d%d%d",&a,&b,&s);
    
    d_a = abs(s-a);
    d_b = abs(s-b);
    
    if(d_a <= d_b || s==1){
        ans = d_a + s;
    }else{
        if(a!=0)
            ans = d_b + min(d_a + a,s-1 + abs(a-1) + 1);
        else
            ans = d_b + s-1 + 2;
    }
    
    printf("%d\n",ans);
    
    return 0;
}