sysbol = {')':'('}

sysbol_l,sysbol_r = sysbol.values(),sysbol.keys()

def check(s):
   arr = []
   for c in s:
   if c in sysbol_l:
     arr.append(c)
   elif c in sysbol_r:
     if arr and arr[-1] ==sysbol[c]:
       arr.pop()
     else:
       return False
   return True