#include <iostream>
#include <cstdio>
#include <cstring>
#include <sstream>
#include <algorithm>
#include <math.h>
#include <map>
#include<functional>
#include <iomanip>
#include <vector>
#include <queue>
#include <set>
#include <typeinfo>
#define PI 3.14159265359
#define INF 99999999;
#define rep(i, n) for(int i=0; i<n; i++)
#define REP(n) rep(i, n)
#define EPS 1e-10
typedef long long ll;
using namespace std;



/*
class Target
{
public:
	vector <string> draw(int n)
	{

	}
};
*/



int main()
{
	int x, y, d;
	int xx, yy, num = 0;
	
	cin >> x >> y >> d;
	for (xx=d; xx>=0; xx--)
	{
		yy = d - xx;
		if (xx <= x && yy <= y) num++;
	}
	cout << num << endl;
	
	return 0;
}