S: S "+" T
S: T
T: T "*" F
T: F
F: "(" S ")"
F: "0"
F: "1"
F: "2"
F: "3"
F: "4"
F: "5"
F: "6"
F: "7"
F: "8"
F: "9"
F: "0" F
F: "1" F
F: "2" F
F: "3" F
F: "4" F
F: "5" F
F: "6" F
F: "7" F
F: "8" F
F: "9" F