#include <bits/stdc++.h>

using namespace std;

#define INF 2000000000
#define MOD 1000000007
typedef long long ll;
typedef pair<int, int> P;


int main()
{
	ll x, y ,d;
	cin >> x >> y >> d;
	int ret=0;
	for (int i = 0; i <= x; i++) {
		if (d-i<=y&&d-i>=0) {
			ret++;
		}
	}
	cout << ret << endl;
}