public static void main ( String [ ] args ) {
  Scanner omkar = new Scanner ( System . in ) ;
  int n = omkar . nextInt ( ) ;
  int m = n / 2 + 1 ;
  System . out . println ( "" + m ) ;
  for ( int i = 1 ;
  i <= m ;
  i ++ ) {
    System . out . println ( "1 " + i ) ;
  }
  for ( int i = 1 ;
  i <= n - m ;
  i ++ ) {
    System . out . println ( ( i + 1 ) + " " + m ) ;
  }
}

public static void main ( String [ ] args ) { Scanner omkar = new Scanner ( System . in ) ; int n = omkar . nextInt ( ) ; int m = n / 2 + 1 ; System . out . println ( " " + m ) ; for ( int i = 1 ; i <= m ; i ++ ) { System . out . println ( "1 ▁ " + i ) ; } for ( int i = 1 ; i <= n - m ; i ++ ) { System . out . println ( ( i + 1 ) + " ▁ " + m ) ; } }
(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)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (string_literal) right: (identifier))))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (string_literal) right: (identifier))))))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (binary_expression left: (identifier) right: (identifier))) update: (update_expression (identifier)) body: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (string_literal)) right: (identifier)))))))))