premise: Two men in a an alleyway, one with his hands in his pockets looking one way the other looking behind him. hypothesis: a man watches tv at home.
contradiction: There cannot be both two men and one man (implied by the word 'a'). The men cannot be both in an alleyway (outside) and at home (inside). If the man is looking one way while the other man looks behind him, they cannot both be watching tv.