Problem:
Score : 100 points

Problem Statement

We have two bottles for holding water.

Bottle 1 can hold up to A milliliters of water, and now it contains B milliliters of water.

Bottle 2 contains C milliliters of water.

We will transfer water from Bottle 2 to Bottle 1 as much as possible.

How much amount of water will remain in Bottle 2?

Constraints

All values in input are integers.

1 \leq B \leq A \leq 20

1 \leq C \leq 20

Input

Input is given from Standard Input in the following format:

A B C

Output

Print the integer representing the amount of water, in milliliters, that will remain in Bottle 2.

Sample Input 1

6 4 3

Sample Output 1

1

We will transfer two milliliters of water from Bottle 2 to Bottle 1, and one milliliter of water will remain in Bottle 2.

Sample Input 2

8 3 9

Sample Output 2

4

Sample Input 3

12 3 7

Sample Output 3

0

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <numeric>
#include <cmath>
#include <tuple>
#include <bitset>
#include <utility>
#include <climits>
#include <iomanip>

#define push emplace_back
#define each(i, x) for (auto i=0; i < x; i++)
using ull = unsigned long long;
constexpr auto mod = 1000000007;
constexpr auto INF = ULLONG_MAX;

using namespace std;
template <typename T> inline void dump(const T& x) { cout << "[" << x << "]" << endl; }
template <typename T> inline void dump(const vector<T>& x) { for (const auto v : x) { cout << v << " "; } cout << endl; }
template <typename T> inline void sort_asc(vector<T>& x) { std::sort(x.begin(), x.end()); }
template <typename T> inline void sort_desc(vector<T>& x) { std::sort(x.begin(), x.end(), greater<T>()); }
template <typename T> inline T max_value(vector<T>& x) { return *max_element(x.begin(), x.end()); }
template <typename T> inline T min_value(vector<T>& x) { return *min_element(x.begin(), x.end()); }
template <typename T> inline T sum_value(vector<T>& x) { return accumulate(x.begin(), x.end(), 0ULL); }

int main() {
  ull a, b, c;
  cin >> a >> b >> c;

  if (c + b > a) {
    cout << c + b - a << endl;
  } else {
    cout << 0 << endl;
  }

  return 0;
}