public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int h = sc . nextInt ( ) ;
  int w = sc . nextInt ( ) ;
  sc . nextLine ( ) ;
  cv = new char [ h ] [ w ] ;
  for ( int i = 0 ;
  i < h ;
  i ++ ) {
    String str = sc . nextLine ( ) ;
    for ( int j = 0 ;
    j < w ;
    j ++ ) {
      cv [ i ] [ j ] = str . charAt ( j ) ;
    }
  }
  boolean flg = true ;
  boolean up , down , left , right ;
  for ( int i = 0 ;
  i < h && flg ;
  i ++ ) {
    for ( int j = 0 ;
    j < w && flg ;
    j ++ ) {
      if ( isBlack ( i , j ) ) {
        up = isBlack ( i - 1 , j ) ;
        down = isBlack ( i + 1 , j ) ;
        left = isBlack ( i , j - 1 ) ;
        right = isBlack ( i , j + 1 ) ;
        if ( ! ( up || down || left || right ) ) {
          flg = false ;
        }
      }
    }
  }
  if ( flg ) {
    System . out . println ( "Yes" ) ;
  }
  else {
    System . out . println ( "No" ) ;
  }
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int h = sc . nextInt ( ) ; int w = sc . nextInt ( ) ; sc . nextLine ( ) ; cv = new char [ h ] [ w ] ; for ( int i = 0 ; i < h ; i ++ ) { String str = sc . nextLine ( ) ; for ( int j = 0 ; j < w ; j ++ ) { cv [ i ] [ j ] = str . charAt ( j ) ; } } boolean flg = true ; boolean up , down , left , right ; for ( int i = 0 ; i < h && flg ; i ++ ) { for ( int j = 0 ; j < w && flg ; j ++ ) { if ( isBlack ( i , j ) ) { up = isBlack ( i - 1 , j ) ; down = isBlack ( i + 1 , j ) ; left = isBlack ( i , j - 1 ) ; right = isBlack ( i , j + 1 ) ; if ( ! ( up || down || left || right ) ) { flg = false ; } } } } if ( flg ) { System . out . println ( " Yes " ) ; } else { System . out . println ( " No " ) ; } }
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(assignment_expression left: (identifier) right: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (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: (block (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: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (identifier)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))))))) (local_variable_declaration type: (boolean_type) declarator: (variable_declarator name: (identifier) value: (true))) (local_variable_declaration type: (boolean_type) declarator: (variable_declarator name: (identifier)) declarator: (variable_declarator name: (identifier)) declarator: (variable_declarator name: (identifier)) declarator: (variable_declarator name: (identifier))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (identifier)) update: (update_expression (identifier)) body: (block (for_statement init: (local_variable_declaration type: (integral_type) 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(method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))))))