public static void main ( String [ ] args ) {
  Scanner stdIn = new Scanner ( System . in ) ;
  long n = stdIn . nextLong ( ) , t = stdIn . nextLong ( ) , tmp = stdIn . nextLong ( ) , a , i , s = 0 ;
  for ( i = 1 ;
  i < n ;
  i ++ ) {
    a = stdIn . nextLong ( ) ;
    if ( t > a - tmp ) s += a - tmp ;
    else s += t ;
    tmp = a ;
  }
  s += t ;
  System . out . println ( s ) ;
}

public static void main ( String [ ] args ) { Scanner stdIn = new Scanner ( System . in ) ; long n = stdIn . nextLong ( ) , t = stdIn . nextLong ( ) , tmp = stdIn . nextLong ( ) , a , i , s = 0 ; for ( i = 1 ; i < n ; i ++ ) { a = stdIn . nextLong ( ) ; if ( t > a - tmp ) s += a - tmp ; else s += t ; tmp = a ; } s += t ; System . out . println ( s ) ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (field_access object: (identifier) field: (identifier)))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) declarator: (variable_declarator name: (identifier)) declarator: (variable_declarator name: (identifier)) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (for_statement init: (assignment_expression left: (identifier) right: (decimal_integer_literal)) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (binary_expression left: (identifier) right: (identifier)))) consequence: (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (identifier)))) alternative: (expression_statement (assignment_expression left: (identifier) right: (identifier)))) (expression_statement (assignment_expression left: (identifier) right: (identifier))))) (expression_statement (assignment_expression left: (identifier) right: (identifier))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))