-module(prog). -export([main/0]). same(X,X) -> true; same(_,_) -> false. main() -> io:format("~p ~p ~p~n", [a, a, same(a, a)]), io:format("~p ~p ~p~n", [a, b, same(a, b)]), io:format("~p ~p ~p~n", [{1,{2,{3}}}, {1,{2,{3}}}, same({1,{2,{3}}},{1,{2,{3}}})]), io:format("~p ~p ~p~n", [{1,{2,{3}}}, {1,{2,{4}}}, same({1,{2,{3}}},{1,{2,{4}}})]), true.