#include <bits/stdc++.h>
using namespace std;
int main(){
int a,b,s;
cin>>a>>b>>s;
if (a <= b) {
 cout << (a == 0 ? 1 : 0) + min(abs(s - b), abs(s - a)) + s << endl;
} else {
 cout << (abs(s - b) < abs(s - a) ? a + abs(s - b) : a) << endl;
}
}