"S" -> ( "S" ) "S"
"S" -> 
"S" -> ( "S" ] "S"

the productions below might be helpful

Letter -> "a";
Letter -> "b";
Letter -> "c";
Letter -> "d";
Letter -> "e";
Letter -> "f";
Letter -> "g";
Letter -> "h";
Letter -> "i";
Letter -> "j";
Letter -> "k";
Letter -> "l";
Letter -> "m";
Letter -> "n";
Letter -> "o";
Letter -> "p";
Letter -> "q";
Letter -> "r";
Letter -> "s";
Letter -> "t";
Letter -> "u";
Letter -> "v";
Letter -> "w";
Letter -> "x";
Letter -> "y";
Letter -> "z";
Letter -> "A";
Letter -> "B";
Letter -> "C";
Letter -> "D";
Letter -> "E";
Letter -> "F";
Letter -> "G";
Letter -> "H";
Letter -> "I";
Letter -> "J";
Letter -> "K";
Letter -> "L";
Letter -> "M";
Letter -> "N";
Letter -> "O";
Letter -> "P";
Letter -> "Q";
Letter -> "R";
Letter -> "S";
Letter -> "T";
Letter -> "U";
Letter -> "V";
Letter -> "W";
Letter -> "X";
Letter -> "Y";
Letter -> "Z";
Digit -> "0";
Digit -> "1";
Digit -> "2";
Digit -> "3";
Digit -> "4";
Digit -> "5";
Digit -> "6";
Digit -> "7";
Digit -> "8";
Digit -> "9";