#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, k, t;
  cin >> n >> k >> t;
  if (t <= k) {
    cout << t << endl;
  } else if (t > k && t <= n) {
    cout << k << endl;
  } else {
    cout << k - abs(n - t) << endl;
  }
  return 0;
}
