public static void main ( String args [ ] ) {
  FastScanner input = new FastScanner ( ) ;
  int n = input . nextInt ( ) ;
  String s = input . next ( ) ;
  int l = 0 , r = 0 , u = 0 , d = 0 ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    if ( s . charAt ( i ) == 'U' ) u ++ ;
    else if ( s . charAt ( i ) == 'D' ) d ++ ;
    else if ( s . charAt ( i ) == 'L' ) l ++ ;
    else r ++ ;
  }
  long ans = Math . min ( l , r ) * 2 + Math . min ( u , d ) * 2 ;
  System . out . println ( ans ) ;
}

public static void main ( String args [ ] ) { FastScanner input = new FastScanner ( ) ; int n = input . nextInt ( ) ; String s = input . next ( ) ; int l = 0 , r = 0 , u = 0 , d = 0 ; for ( int i = 0 ; i < n ; i ++ ) { if ( s . charAt ( i ) == ' U ' ) u ++ ; else if ( s . charAt ( i ) == ' D ' ) d ++ ; else if ( s . charAt ( i ) == ' L ' ) l ++ ; else r ++ ; } long ans = Math . min ( l , r ) * 2 + Math . min ( u , d ) * 2 ; System . out . println ( ans ) ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (type_identifier) name: (identifier) dimensions: (dimensions))) body: (block (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)))) (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: (expression_statement (update_expression (identifier))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal))) consequence: (expression_statement (update_expression (identifier))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal))) consequence: (expression_statement (update_expression (identifier))) alternative: (expression_statement (update_expression (identifier)))))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (identifier))) right: (decimal_integer_literal)) right: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (identifier))) right: (decimal_integer_literal))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))