#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;
}
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