Evil Poetatoes come and eat ur flesh :3 WAFFLES!
The program failed because there was an extra parenthesis in the expression. Note that the plural form--parentheses--is probably more common: References to requirements should include their ID...
open parenthesis
To notify how much of a group of atoms there are example: Mg + NH4 = Mg(NH4)2 signifying that there are 2 ammonium molecules in the chemical formula