#include <iostream>
using namespace std;

const int MAX_SIZE = 1000;

int main() {
	int n, fr[MAX_SIZE + 1] = {0};
	
	cin >> n;
	int m = (n+(n - 1));
	for(int i = 1; i <= n; ++i){
		int currentElement;
		cin >> currentElement;
		++fr[currentElement];
	}
	
	for(int i = 1; i <= MAX_SIZE; ++i){
		if(fr[i] == 1){
			cout << i << " ";
			
			
		}
		//cout << fr[i] << " ";
	}
	return 0;
}