There is a special form for boolean formulas called "Conjunctive Normal Form" (CNF). A problem in this form consists of clauses connected with and operators, where each clause only contains variables connected with or operators. The variables can appear negated, but only variables can be directly negated, something like !(a && b) is not allowed. An example boolean formula in CNF form is:
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Филолог заявил о массовой отмене обращения на «вы» с большой буквы09:36，更多细节参见heLLoword翻译官方下载
When they began their first attempt of the walk, they were waved off by members of the local air ambulance crew.