Check String for number

/**
Check if a given string input is a number, can have dollar ($) symbol at begining, can be negative or positve
*/
import java.util.*;
import java.util.regex.*;

public class CheckStringNumber{

public static void main(String args[]){
System.out.println(args.length);
String input = args[0];
String reg = "[-+]*[$]*[\\d]+[\\.]*[\\d]*";
Pattern pat = Pattern.compile(reg);
Matcher mat = pat.matcher(input);
if(mat.find() && mat.group().equals(input)){
System.out.println("valid number");
}else{
System.out.println("NOT A VALID number");
}
}

}