#include <iostream>
#include <vector>
#include <algorithm>
 
int main()
{
    enum class En{A, B};
    std::vector<En> vec{En::A, En::B, En::A, En::B, En::A, En::B, En::A};
 
    for(const auto& i : vec) std::cout << int(i) << ", ";
    std::cout << std::endl;
 
    auto elem = vec.front();
	vec.erase(	std::remove(std::begin(vec), std::end(vec), elem), 
          		std::end(vec));
 
    for(const auto& i : vec) std::cout << int(i) << ", ";
    std::cout << std::endl;
 
    return 0;
}

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