#include #include #include int main() { int N; std::cin >> N; std::vector Item; Item.resize(N * 3); for (int i = 0; i < N * 3; i++) { std::cin >> Item[i]; } std::array ItemAll; for (int i = 0; i < 10; i++) { ItemAll[i] = 0; } for (int i = 0, n = (unsigned)Item.size(); i < n; i++) { ItemAll[Item[i]-1]++; } int PowerUp = 0; for (int i = 0; i < 10; i++) { PowerUp += ItemAll[i] / 2; ItemAll[i] %= 2; } for (int i = 1; i < 10; i++) { ItemAll[0] += ItemAll[i]; } PowerUp += ItemAll[0] / 4; std::cout << PowerUp << std::endl; return 0; }