public static void main ( String [ ] args ) {
  Scanner in = new Scanner ( System . in ) ;
  int n = in . nextInt ( ) ;
  int top_sum = 0 ;
  int bottom_sum = 0 ;
  boolean diff = false ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    int top = in . nextInt ( ) ;
    int bottom = in . nextInt ( ) ;
    if ( ( bottom + top ) % 2 != 0 ) diff = true ;
    top_sum += top ;
    bottom_sum += bottom ;
  }
  if ( top_sum % 2 == 0 && bottom_sum % 2 == 0 ) System . out . println ( 0 ) ;
  else if ( top_sum % 2 != 0 && bottom_sum % 2 != 0 && n != 1 && diff ) System . out . println ( 1 ) ;
  else System . out . println ( - 1 ) ;
}

public static void main ( String [ ] args ) { Scanner in = new Scanner ( System . in ) ; int n = in . nextInt ( ) ; int top_sum = 0 ; int bottom_sum = 0 ; boolean diff = false ; for ( int i = 0 ; i < n ; i ++ ) { int top = in . nextInt ( ) ; int bottom = in . nextInt ( ) ; if ( ( bottom + top ) % 2 != 0 ) diff = true ; top_sum += top ; bottom_sum += bottom ; } if ( top_sum % 2 == 0 && bottom_sum % 2 == 0 ) System . out . println ( 0 ) ; else if ( top_sum % 2 != 0 && bottom_sum % 2 != 0 && n != 1 && diff ) System . out . println ( 1 ) ; else System . out . println ( - 1 ) ; }
(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: (decimal_integer_literal))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (local_variable_declaration type: (boolean_type) declarator: (variable_declarator name: (identifier) value: (false))) (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 (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: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) right: (decimal_integer_literal)) right: (decimal_integer_literal))) consequence: (expression_statement (assignment_expression left: (identifier) right: (true)))) (expression_statement (assignment_expression left: (identifier) right: (identifier))) (expression_statement (assignment_expression left: (identifier) right: (identifier))))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)) right: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)))) consequence: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (decimal_integer_literal)))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (binary_expression left: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)) right: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal))) right: (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (identifier))) consequence: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (decimal_integer_literal)))) alternative: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (unary_expression operand: (decimal_integer_literal)))))))))