molecule
molecule_rule
EOF
molecule_rule
molecule_group
molecule_group
element_group
single_element
molecule_group
molecule_group
element_group
element
count
single_element
element
element
'C'
'H'
'N'
'O'
'P'
'S'
'Br'
'I'
'F'
'Cl'
'As'
count
number
'-'
number
number
digit
digit
number
digit
'0'
'1'
'2'
'3'
'4'
'5'
'6'
'7'
'8'
'9'