public static void main ( String [ ] args ) throws IOException {
  BufferedReader reader = new BufferedReader ( new InputStreamReader ( System . in ) ) ;
  int n = Integer . parseInt ( reader . readLine ( ) ) ;
  Integer l = null , u = null ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    String [ ] line = reader . readLine ( ) . split ( " " ) ;
    int x = Integer . parseInt ( line [ 1 ] ) ;
    switch ( line [ 0 ] ) {
      case ">" : if ( line [ 2 ] . equals ( "Y" ) ) {
        if ( l == null || l <= x ) l = x + 1 ;
      }
      else if ( u == null || u > x ) u = x ;
      break ;
      case "<" : if ( line [ 2 ] . equals ( "Y" ) ) {
        if ( u == null || u >= x ) u = x - 1 ;
      }
      else if ( l == null || l < x ) l = x ;
      break ;
      case ">=" : if ( line [ 2 ] . equals ( "Y" ) ) {
        if ( l == null || l < x ) l = x ;
      }
      else if ( u == null || u >= x ) u = x - 1 ;
      break ;
      default : if ( line [ 2 ] . equals ( "Y" ) ) {
        if ( u == null || u > x ) u = x ;
      }
      else if ( l == null || l <= x ) l = x + 1 ;
    }
  }
  if ( l == null ) System . out . println ( u ) ;
  else if ( u == null || l <= u ) System . out . println ( l ) ;
  else System . out . println ( "Impossible" ) ;
}

public static void main ( String [ ] args ) throws IOException { BufferedReader reader = new BufferedReader ( new InputStreamReader ( System . in ) ) ; int n = Integer . parseInt ( reader . readLine ( ) ) ; Integer l = null , u = null ; for ( int i = 0 ; i < n ; i ++ ) { String [ ] line = reader . readLine ( ) . split ( " ▁ " ) ; int x = Integer . parseInt ( line [ 1 ] ) ; switch ( line [ 0 ] ) { case " > " : if ( line [ 2 ] . equals ( " Y " ) ) { if ( l == null || l <= x ) l = x + 1 ; } else if ( u == null || u > x ) u = x ; break ; case " < " : if ( line [ 2 ] . equals ( " Y " ) ) { if ( u == null || u >= x ) u = x - 1 ; } else if ( l == null || l < x ) l = x ; break ; case " > = " : if ( line [ 2 ] . equals ( " Y " ) ) { if ( l == null || l < x ) l = x ; } else if ( u == null || u >= x ) u = x - 1 ; break ; default : if ( line [ 2 ] . equals ( " Y " ) ) { if ( u == null || u > x ) u = x ; } else if ( l == null || l <= x ) l = x + 1 ; } } if ( l == null ) System . out . println ( u ) ; else if ( u == null || l <= u ) System . out . println ( l ) ; else System . out . println ( " Impossible " ) ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) (throws (type_identifier)) 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: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (null_literal)) declarator: (variable_declarator name: (identifier) value: (null_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: (type_identifier) 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 (string_literal))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (array_access array: (identifier) index: (decimal_integer_literal)))))) (switch_expression condition: (parenthesized_expression (array_access array: (identifier) index: (decimal_integer_literal))) body: (switch_block (switch_block_statement_group (switch_label (string_literal)) (if_statement condition: (parenthesized_expression (method_invocation object: (array_access array: (identifier) index: (decimal_integer_literal)) name: (identifier) arguments: (argument_list (string_literal)))) consequence: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (null_literal)) right: (binary_expression left: (identifier) right: (identifier)))) consequence: (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (decimal_integer_literal)))))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (null_literal)) right: (binary_expression left: (identifier) right: (identifier)))) consequence: (expression_statement (assignment_expression left: (identifier) right: (identifier))))) (break_statement)) (switch_block_statement_group (switch_label (string_literal)) (if_statement condition: (parenthesized_expression (method_invocation object: (array_access array: (identifier) index: (decimal_integer_literal)) name: (identifier) arguments: (argument_list (string_literal)))) consequence: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (null_literal)) right: (binary_expression left: (identifier) right: (identifier)))) consequence: (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (decimal_integer_literal)))))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (null_literal)) right: (binary_expression left: (identifier) right: (identifier)))) consequence: (expression_statement (assignment_expression left: (identifier) right: (identifier))))) (break_statement)) (switch_block_statement_group (switch_label (string_literal)) (if_statement condition: (parenthesized_expression (method_invocation object: (array_access array: (identifier) index: (decimal_integer_literal)) name: (identifier) arguments: (argument_list (string_literal)))) consequence: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (null_literal)) right: (binary_expression left: (identifier) right: (identifier)))) consequence: (expression_statement (assignment_expression left: (identifier) right: (identifier))))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (null_literal)) right: (binary_expression left: (identifier) right: (identifier)))) consequence: (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (decimal_integer_literal)))))) (break_statement)) (switch_block_statement_group (switch_label) (if_statement condition: (parenthesized_expression (method_invocation object: (array_access array: (identifier) index: (decimal_integer_literal)) name: (identifier) arguments: (argument_list (string_literal)))) consequence: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (null_literal)) right: (binary_expression left: (identifier) right: (identifier)))) consequence: (expression_statement (assignment_expression left: (identifier) right: (identifier))))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (null_literal)) right: (binary_expression left: (identifier) right: (identifier)))) consequence: (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (decimal_integer_literal))))))))))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (null_literal))) consequence: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier)))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (null_literal)) right: (binary_expression left: (identifier) right: (identifier)))) consequence: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier)))) alternative: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))))))