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 <algorithm>
#include <functional>
#include <string>
#include <vector>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <map>
#include <set>
#include <list>
#include <unordered_set>
#include <unordered_map>
#include <iomanip>
#include <limits>

using namespace std;

using i64 = int64_t;
using P = pair<i64, i64>;

struct edge {
    i64 from, to, cost;
    edge(i64 from, i64 to) : from(from), to(to), cost(1) {}
    edge(i64 from, i64 to, i64 cost) : from(from), to(to), cost(cost) {}
};
using Graph = vector<vector<edge>>;

constexpr i64 INF = std::numeric_limits<i64>::max();
constexpr i64 SINF = std::numeric_limits<i64>::max() / 10;
const i64 dx[4] = { 0,1,0,-1 }, dy[4] = { -1,0,1,0 };
//const i64 dx[5] = {-1,0,0,0,1}, dy[5] = {0,-1,0,1,0};
//const i64 dx[8] = {-1,0,1,1,1,0,-1,-1}, dy[8] = {1,1,1,0,-1,-1,-1,0};
//const i64 dx[9] = {-1,0,1,1,1,0,-1,-1,0}, dy[9] = {1,1,1,0,-1,-1,-1,0,0};

// http://beet-aizu.hatenablog.com/entry/2018/04/08/145516
template<typename T>
vector<T> make_v(size_t a) { return vector<T>(a); }

template<typename T, typename... Ts>
auto make_v(size_t a, Ts... ts) {
    return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}

template<typename T, typename V>
typename enable_if<is_class<T>::value == 0>::type
fill_v(T& t, const V& v) { t = v; }

template<typename T, typename V>
typename enable_if<is_class<T>::value != 0>::type
fill_v(T& t, const V& v) {
    for (auto& e : t) fill_v(e, v);
}

struct IoSetup {
    IoSetup() {
        cin.tie(nullptr);
        ios::sync_with_stdio(false);
        cout << fixed << setprecision(10);
        cerr << fixed << setprecision(10);
    }
} iosetup;

void solve(long long A, long long B, long long C){
    cout << max(0LL, C - (A - B)) << endl;
}

int main() {
    long long A;
    scanf("%lld",&A);
    long long B;
    scanf("%lld",&B);
    long long C;
    scanf("%lld",&C);
    solve(A, B, C);
    return 0;
}