#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES

#include "bits/stdc++.h"
#include <vector>
#include <set>
#include <string>
#include <queue>
#include <list>
#define REP(i,a,b) for(i=a;i<b;++i)
#define rep(i,n) REP(i,0,n)
#define ll long long
#define ull unsigned ll
typedef long double ld;
#define SQR(X)  ( (X)*(X) )
#define CUBE(X) ( (X)*(X)*(X) )
#define ALL(a) (a).begin(),(a).end()
// #define int ll

#define dump(x)  cerr << #x << " = " << (x) << endl
using namespace std;

bool test = 0;


void reader(int &a){scanf("%d",&a);};
void reader(double &a){scanf("%lf",&a);};
void reader(char a[]){scanf("%s",a);};
// void reader(string& a){cin >> a;};
template<class T,class U>
void reader(T& t,U& u){
  reader(t); reader(u);
}
template<class T,class U,class V>
void reader(T& t,U& u,V& v){
  reader(t); reader(u); reader(v);
}

void writer(int a,char c) {printf("%d",a); putchar(c);}
void writer(double a,char c) {printf("%.20lf",a); putchar(c);}
void writer(char a[]) {printf("%s",a);};
void writer(char a[],char c) {printf("%s",a);putchar(c);};
template<class T>
void writerLn(T t){
  writer(t,'\n');
}
template<class T,class U>
void writerLn(T t,U u){
  writer(t,' ');
  writer(u,'\n');
}
template<class T,class U,class V>
void writerLn(T t,U u,V v){
  writer(t,' '); 
  writer(u,' '); 
  writer(v,'\n'); 
}

signed main(){
  int i,j,k,l;
  int N;
  int A[10005];
  cin >> N;
  rep(i,N) cin >> A[i];
  int sum;
  cin >> sum;
  rep(i,N) {
    sum -= A[i];
  }
  cout << -sum << endl;
  return 0;
}