#include <iostream>

using namespace std;

int main() {
    int n;
    int t_true = 0;
    int t_yuki = 0;
    
    cin >> n;
    
    int tmp;
    for (int i = 0; i < n; i++) {
        cin >> tmp;
        t_true += tmp;
    }
    
    cin >> t_yuki;
    cout << t_true - t_yuki << endl;
    
    return 0;
}