#include <cstdio>
#include <climits>
#include <iostream>
#include <string>
#include <vector>
#include <set>
#include <cmath>
#include <stack>
#include <algorithm>
#include <iomanip>
#include <map>
#include <queue>
#include <functional>
#include <numeric>
#include <chrono>
#include <cstdlib>
using ll = long long;
using namespace std;

const ll MOD = 1e9 + 7;
const double pi = acos(-1);
typedef pair<int, int> P;
#define REP(i, n) for (int(i) = 0; (i) < (n); ++(i))
#define repi(i, a, b) for (int i = int(a); i < int(b); ++i)
#define EPS 1e-4
#define OUTPUT(i) (cout << (ll)i << endl)
#define ALL(a) ((a).begin(), (a).end())

bool operator<(const pair<ll, ll> &a, const pair<ll, ll> &b)
{

    if (a.first == b.first)
        return a.second < b.second;

    return a.first < b.first;
}

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    //cout << fixed << setprecision(15);

    ll x, y, d;
    cin >> x >> y >> d;
    int cnt = 0;

    if (x + y < d)
    {
        cout << 0 << endl;
        return 0;
    }

    for (int i = 0; i <= x; ++i)
    {
        if (d - i <= y && d - i >= 0)
            cnt++;
    }
    cout << cnt << endl;
    return 0;
}