// No.369 足し間違い
// https://yukicoder.me/problems/no/369
//
using namespace std;

#include <iostream>
#include <vector>
#include <numeric>

int solve(vector<int> &numbers, int v);

int main() {
    unsigned int N;
    cin >> N;
    vector<int> numbers(N);
    for (auto i = 0; i < N; i++)
        cin >> numbers[i];
    int v;
    cin >> v;

    int ans = solve(numbers, v);
    cout << ans << endl;
}

int solve(vector<int> &numbers, int v) {
    int total = accumulate(numbers.begin(), numbers.end(), 0);
    return total - v;
}