public static void main ( String ... orange ) throws Exception {
  Scanner input = new Scanner ( System . in ) ;
  int numCases = input . nextInt ( ) ;
  for ( int n = 0 ;
  n < numCases ;
  n ++ ) {
    int N = input . nextInt ( ) ;
    int L = input . nextInt ( ) ;
    String [ ] Gs = new String [ N ] ;
    for ( int i = 0 ;
    i < N ;
    i ++ ) Gs [ i ] = input . next ( ) ;
    String B = input . next ( ) ;
    boolean bad = false ;
    for ( String G : Gs ) if ( G . equals ( B ) ) bad = true ;
    if ( bad ) {
      System . out . printf ( "Case #%d: IMPOSSIBLE\n" , n + 1 ) ;
      continue ;
    }
    if ( L == 1 ) {
      System . out . printf ( "Case #%d: 0 ?\n" , n + 1 ) ;
      continue ;
    }
    StringBuilder p1 = new StringBuilder ( ) ;
    StringBuilder p2 = new StringBuilder ( ) ;
    for ( int i = 0 ;
    i < L ;
    i ++ ) {
      if ( i == L - 1 ) {
        if ( i % 2 == 0 ) p2 . append ( "?1" ) ;
        else p1 . append ( "?1" ) ;
      }
      else if ( i % 2 == 0 ) {
        p1 . append ( "10" ) ;
        p2 . append ( "?" ) ;
      }
      else {
        p1 . append ( "?" ) ;
        p2 . append ( "10" ) ;
      }
    }
    System . out . printf ( "Case #%d: %s %s\n" , n + 1 , p1 , p2 ) ;
  }
}

public static void main ( String ... orange ) throws Exception { Scanner input = new Scanner ( System . in ) ; int numCases = input . nextInt ( ) ; for ( int n = 0 ; n < numCases ; n ++ ) { int N = input . nextInt ( ) ; int L = input . nextInt ( ) ; String [ ] Gs = new String [ N ] ; for ( int i = 0 ; i < N ; i ++ ) Gs [ i ] = input . next ( ) ; String B = input . next ( ) ; boolean bad = false ; for ( String G : Gs ) if ( G . equals ( B ) ) bad = true ; if ( bad ) { System . out . printf ( " Case ▁ # % d : ▁ IMPOSSIBLE \n " , n + 1 ) ; continue ; } if ( L == 1 ) { System . out . printf ( " Case ▁ # % d : ▁ 0 ▁ ? \n " , n + 1 ) ; continue ; } StringBuilder p1 = new StringBuilder ( ) ; StringBuilder p2 = new StringBuilder ( ) ; for ( int i = 0 ; i < L ; i ++ ) { if ( i == L - 1 ) { if ( i % 2 == 0 ) p2 . append ( " ? 1" ) ; else p1 . append ( " ? 1" ) ; } else if ( i % 2 == 0 ) { p1 . append ( "10" ) ; p2 . append ( " ? " ) ; } else { p1 . append ( " ? " ) ; p2 . append ( "10" ) ; } } System . out . printf ( " Case ▁ # % d : ▁ % s ▁ % s \n " , n + 1 , p1 , p2 ) ; } }
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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)))) (local_variable_declaration type: (array_type element: (type_identifier) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (type_identifier) dimensions: (dimensions_expr (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: (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: 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name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (binary_expression left: (identifier) right: (decimal_integer_literal)))) consequence: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal))) consequence: (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal)))) alternative: (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal)))))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: 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