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The C Preprocessor / Any C or C++ Implementation, 362 bytes
#define N()
#define D(I) I N()
#define E(...) R(R(R(__VA_ARGS__)))
#define R(...) T(T(T(__VA_ARGS__)))
#define T(...) Y(Y(Y(__VA_ARGS__)))
#define Y(...) U(U(U(__VA_ARGS__)))
#define U(...) I(I(I(__VA_ARGS__)))
#define I(...) O(O(O(__VA...