The NOTXDIGIT function
                  searches a string for the first occurrence of any character that is
                  not a digit or an uppercase or lowercase A, B, C, D, E, or F. If such
                  a character is found, NOTXDIGIT returns the position in the string
                  of that character. If no such character is found, NOTXDIGIT returns
                  a value of 0.
                  
               
 
               
               If you use only one
                  argument, NOTXDIGIT begins the search at the beginning of the string.
                  If you use two arguments, the absolute value of the second argument, 
start, specifies the position at which to begin
                  the search. The direction in which to search is determined in the
                  following way:  
                  
                  
                  
                     
                     
                        
                        - 
                           
                           
If the value of 
start is positive, the search proceeds to the
                                 right. 
                                 
                              
 
                              
                            
                           
                         
                        
                        - 
                           
                           
If the value of 
start is negative, the search proceeds to the
                                 left. 
                                 
                              
 
                              
                            
                           
                         
                        
                        - 
                           
                           
If the value of 
start is less than the negative length of the
                                 string, the search begins at the end of the string. 
                                 
                              
 
                              
                            
                           
                         
                        
                     
                     
                    
                  
                
               
               NOTXDIGIT returns a
                  value of zero when one of the following is true: 
                  
                  
                  
                     
                     
                        
                        - 
                           
                           
The character that you are searching
                                 for is not found.
                                 
                              
 
                              
                            
                           
                         
                        
                        - 
                           
                           
The value of 
start is greater than the length of the string.
                                 
                              
 
                              
                            
                           
                         
                        
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