public static void main ( String args [ ] ) {
  try {
    BufferedReader br = new BufferedReader ( new InputStreamReader ( System . in ) ) ;
    MyScanner sc = new MyScanner ( ) ;
    int h = sc . nextInt ( ) , w = sc . nextInt ( ) ;
    int sum = 0 ;
    for ( int i = 0 ;
    i < h ;
    ++ i ) {
      char [ ] a = br . readLine ( ) . toCharArray ( ) ;
      for ( int j = 0 ;
      j < w ;
      ++ j ) {
        if ( a [ j ] == '#' ) {
          ++ sum ;
        }
      }
    }
    if ( sum == h + w - 1 ) {
      System . out . println ( "Possible" ) ;
    }
    else {
      System . out . println ( "Impossible" ) ;
    }
  }
  catch ( IOException e ) {
    e . printStackTrace ( ) ;
  }
}

public static void main ( String args [ ] ) { try { BufferedReader br = new BufferedReader ( new InputStreamReader ( System . in ) ) ; MyScanner sc = new MyScanner ( ) ; int h = sc . nextInt ( ) , w = sc . nextInt ( ) ; int sum = 0 ; for ( int i = 0 ; i < h ; ++ i ) { char [ ] a = br . readLine ( ) . toCharArray ( ) ; for ( int j = 0 ; j < w ; ++ j ) { if ( a [ j ] == ' # ' ) { ++ sum ; } } } if ( sum == h + w - 1 ) { System . out . println ( " Possible " ) ; } else { System . out . println ( " Impossible " ) ; } } catch ( IOException e ) { e . printStackTrace ( ) ; } }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (type_identifier) name: (identifier) dimensions: (dimensions))) body: (block (try_statement body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (object_creation_expression type: (type_identifier) arguments: (argument_list (field_access object: (identifier) field: (identifier)))))))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_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))) 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))) (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: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) 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 (if_statement condition: (parenthesized_expression (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (character_literal))) consequence: (block (expression_statement (update_expression (identifier))))))))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (decimal_integer_literal)))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))) alternative: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))))) (catch_clause (catch_formal_parameter (catch_type (type_identifier)) name: (identifier)) body: (block (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))))))))