#include <iostream>
#include <algorithm>
using namespace std;
int main()
{
    int a, b, s;
    cin>>a>>b>>s;
    if (s==1) { cout<<abs(a-1)+1<<endl; return 0; }
    int x=abs(a-s), y=abs(b-s);
    if (x<=y) { cout<<x+s<<endl; return 0; }
    cout<<y+(a?min(x, s-1)+a:s+1)<<endl;
}