The problem to be solved by the present invention is to provide a novel compound having RET inhibitory activity. The present invention also provides a pharmaceutical preparation that 5 is useful for the prevention and/or treatment of RET-related diseases, particularly cancer, based on RET inhibitory activity. The present invention provides a compound represented by Formula (I): 10 wherein A, R 2, and X are as defined in the specification; or a salt thereof. 15