public static void main ( String [ ] args ) {
  Scanner input = new Scanner ( System . in ) ;
  int n = input . nextInt ( ) ;
  String s = input . next ( ) ;
  int cs = 0 , max = 0 , cg = 0 , res = 0 ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    if ( s . charAt ( i ) == 'G' ) {
      max ++ ;
      cg ++ ;
    }
    else {
      cs = cg ;
      cg = 0 ;
    }
    res = Math . max ( res , cs + cg + 1 ) ;
  }
  System . out . println ( Math . min ( res , max ) ) ;
}

public static void main ( String [ ] args ) { Scanner input = new Scanner ( System . in ) ; int n = input . nextInt ( ) ; String s = input . next ( ) ; int cs = 0 , max = 0 , cg = 0 , res = 0 ; for ( int i = 0 ; i < n ; i ++ ) { if ( s . charAt ( i ) == ' G ' ) { max ++ ; cg ++ ; } else { cs = cg ; cg = 0 ; } res = Math . max ( res , cs + cg + 1 ) ; } System . out . println ( Math . min ( res , max ) ) ; }
(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)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal)) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal)) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal)) 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 (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal))) consequence: (block (expression_statement (update_expression (identifier))) (expression_statement (update_expression (identifier)))) alternative: (block (expression_statement (assignment_expression left: (identifier) right: (identifier))) (expression_statement (assignment_expression left: (identifier) right: (decimal_integer_literal))))) (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (decimal_integer_literal)))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (identifier))))))))