#include <bits/stdc++.h>
using namespace std;

typedef long long int ll;
ll MOD = 1000000007;
ll INFL = 1ll << 60;
ll INF = 1 << 28;

// ====================================================================

int main() {
  ll l, r, m;
  cin >> l >> r >> m;
  cout << min(r - l + 1, m) << endl;
}