G = _VT,VN,P,S_
dove:
VT = { 0,1,2,3,4,5,6,7,8,9 }
VN = { , , }
S =
P = {
::= | {} ::= 0 | ::= 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
}