#include <bits/stdc++.h>
using namespace std;
inline void filehandling() {}
void Fn(string STRING) {
  long long n = STRING.length();
  stack<char> STACK;
  long long i = 1;
  while (i < n) {
    if (STRING[i] == '(')
      STACK.push(STRING[i]);
    else {
      if (STACK.empty()) {
        cout << "No" << endl;
        return;
      } else
        STACK.pop();
    }
    i++;
  }
  if (STACK.size() == 1)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
vector<long long> vector_in(long long n) {
  vector<long long> v(n);
  for (long long i = 0; i < n; i++) cin >> v[i];
  return v;
}
void vector_out(vector<long long> v) {
  for (long long i = 0; i < v.size(); i++) cout << v[i] << " ";
  cout << endl;
}
long long vector_sum(vector<long long> v) {
  long long sum;
  for (long long i = 0; i < v.size(); i++) sum += v[i];
  return sum;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  filehandling();
  long long N1, N2, N3;
  cin >> N1;
  cin >> N2;
  cin >> N3;
  long long N4 = N3 + 1;
  N4 -= (N1 > N3 ? 0 : (N3 - N1));
  N4 -= (N2 > N3 ? 0 : (N3 - N2));
  cout << N4 << endl;
}
