premise: Two girls, the one in the background is wearing black, while the other girl in the foreground is wearing khaki shorts, a purple shirt and sneakers and gesturing like she is blowing a kiss. hypothesis: Two girls are dressed the same, and both are covering their mouths with their hands.
contradiction: If both girls are covering their mouths with their hands, one girl cannot be gesturing like she is blowing a kiss. Also, if both girls are dressed the same, one cannot be wearing purple while one wears black.