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:
Мерц резко сменил риторику во время встречи в Китае09:25
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（三）国际运输服务、航天运输服务、对外修理修配服务。
This latest escalation comes days after Pakistan carried out air strikes inside Afghanistan following suicide blasts on its soil (file photo)