public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  String s = sc . nextLine ( ) ;
  for ( int i = 0 ;
  i < s . length ( ) ;
  i ++ ) {
    for ( int j = 1 ;
    j < s . length ( ) ;
    j ++ ) {
      if ( i + j <= s . length ( ) ) {
        String t = s . substring ( i , i + j ) ;
        if ( ! map . containsKey ( t ) ) map . put ( t , 1 ) ;
        else map . put ( t , map . get ( t ) + 1 ) ;
      }
    }
  }
  int ans = 0 ;
  for ( Map . Entry < String , Integer > entry : map . entrySet ( ) ) {
    int k = entry . getValue ( ) ;
    String t = entry . getKey ( ) ;
    if ( k >= 2 && t . length ( ) > ans ) ans = t . length ( ) ;
  }
  System . out . println ( ans ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; String s = sc . nextLine ( ) ; for ( int i = 0 ; i < s . length ( ) ; i ++ ) { for ( int j = 1 ; j < s . length ( ) ; j ++ ) { if ( i + j <= s . length ( ) ) { String t = s . substring ( i , i + j ) ; if ( ! map . containsKey ( t ) ) map . put ( t , 1 ) ; else map . put ( t , map . get ( t ) + 1 ) ; } } } int ans = 0 ; for ( Map . Entry < String , Integer > entry : map . entrySet ( ) ) { int k = entry . getValue ( ) ; String t = entry . getKey ( ) ; if ( k >= 2 && t . length ( ) > ans ) ans = t . length ( ) ; } System . out . println ( ans ) ; }
(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: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) update: (update_expression (identifier)) body: (block (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) consequence: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (binary_expression left: (identifier) right: (identifier)))))) (if_statement condition: (parenthesized_expression (unary_expression operand: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))) consequence: (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (decimal_integer_literal)))) alternative: (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (decimal_integer_literal)))))))))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (enhanced_for_statement type: (generic_type (scoped_type_identifier (type_identifier) (type_identifier)) (type_arguments (type_identifier) (type_identifier))) name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) body: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (identifier)))) consequence: (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))