Two logical spies, M and N, sent reports to Z, the head of the CIA. Z suspected one to be a double agent. The task is to find which spy is trustworthy and always tells the truth, which spy is untrustworthy and always lies, and to evaluate their statements,

,

,

, …, for their truth values. The contents of the statements are classified. For negation, conjunction, disjunction, implication, and equivalence, they used the symbols

,

,

,

,

. For readability, F (for False) is left blank in the truth tables.