public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  String x = sc . next ( ) ;
  if ( n == 1 & x . equals ( "10" ) ) {
    System . out . println ( - 1 ) ;
    return ;
  }
  if ( x . equals ( "10" ) ) {
    while ( n -- > 2 ) {
      x += "0" ;
    }
  }
  else {
    while ( n -- > 1 ) {
      x += "0" ;
    }
  }
  System . out . println ( x ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; String x = sc . next ( ) ; if ( n == 1 & x . equals ( "10" ) ) { System . out . println ( - 1 ) ; return ; } if ( x . equals ( "10" ) ) { while ( n -- > 2 ) { x += "0" ; } } else { while ( n -- > 1 ) { x += "0" ; } } System . out . println ( x ) ; }
(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: (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: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal))))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (unary_expression operand: (decimal_integer_literal))))) (return_statement))) (if_statement condition: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal)))) consequence: (block (while_statement condition: (parenthesized_expression (binary_expression left: (update_expression (identifier)) right: (decimal_integer_literal))) body: (block (expression_statement (assignment_expression left: (identifier) right: (string_literal)))))) alternative: (block (while_statement condition: (parenthesized_expression (binary_expression left: (update_expression (identifier)) right: (decimal_integer_literal))) body: (block (expression_statement (assignment_expression left: (identifier) right: (string_literal))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))