add_four_digit = ("0" : "4") | ("1" : "5") | ("2" : "6") | ("3" : "7")| ("4" : "8") | ("5" : "9") | ("6" : "+0") | ("7" : "+1") | ("8" : "+2") | ("9" : "+3") ;
digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9";
number = digit+;
add_four = add_four_digit number?;
x = CDRewrite["+": "1", "[BOS]", "", (number | "+")*];
m = CDRewrite[("0": "1+") | ("1": "2+") | ("2": "3+") | ("3": "4+") | ("4": "5+") | ("5": "6+") | ("6": "7+") | ("7": "8+") | ("8": "9+") | ("0": "1+") | ("+": "-") | ("7" : "8+"), digit*, digit "+[EOS]"$
y = CDRewrite[("9": "0"), digit,  digit* "+[EOS]", (number | "+" | "-")*];
z = CDRewrite[("1" : "2") | ("2" : "3") | ("3" : "4") | ("4" : "5") | ("5": "6") | ("6" : "7") | ("7": "8") | ("8": "9") | ("9": "10"), "[BOS]", digit* "+[EOS]", (number | "+" | "-")*];
k = CDRewrite[("+": "") | ("-": ""), "", "", (number | "+" | "-")*];
export PROCESS = Optimize[Reverse[add_four] @ m @ y @ z @ k];