#include 
#include 
#include 
 
int main()
{
    std::vector input({ 1, 2, 2, 1, 3, 1, 4 });
 
    std::unordered_set set(input.begin(), input.end());
 
    for (const int &i: set) {
        std::cout << i << " ";
    }
 
    return 0;
}