#define T;template<class
#define O T N>struct
#define W T A,class B>struct
#define U using t=
U int O S W a W a<S<A>,B>:a<A,S<B>>{}O a<t,N>{U N;}W s{U A;}W s<S<A>,S<B>>:s<A,B>{}W m{U int;}O m<N,S<t>>{U N;}W m<A,S<B>>:a<typename m<A,B>::t,A>{}T A,class B,class V=t>struct d:d<typename s<A,B>::t,B,S<V>>{}W d<t,A,B>{U B;};