#include <iostream>
#include <string>
#include <vector>
#include <cmath>
#include <algorithm>
#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <functional>
#include <set>
#include <sstream>
#include <map>
#include <queue>
#include <stack>

using namespace std;

const long long mod=1000000007; 

int main()
{

	int n;
	cin>>n;
	
	int sum;
	cin>>sum;
	for(int i=0;i<n-1;i++){
		int a;
		cin>>a;
		sum+=a;
	}
	
	int t;
	cin>>t;
	cout<<sum-t<<endl;
	return 0;
}