#include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
using namespace std;

#define ll long long
#define INF (1 << 30)
#define INFLL (1LL << 60)

int main() {
	int mx,my,n;
	cin >> mx >> my >> n;
	int p = min(n,mx) + min(n,my) - n;
	p++;
	if(p >= 0) cout << p << endl;
	else cout << 0 << endl;
	return 0;
}