-stoneP = Hailstone <$> (vertexP <* symbolP "@") <*> vertexP
-vertexP = vecify <$> signed decimal <*> (symbolP "," *> signed decimal) <*> (symbolP "," *> signed decimal)
+stoneP = Hailstone <$> vertexP <* symbolP "@" <*> vertexP
+vertexP = vecify <$> signed decimal <* symbolP ","
+ <*> signed decimal <* symbolP ","
+ <*> signed decimal