static long findF_N ( long n ) {
  long ans = 0 ;
  for ( long i = 0 ;
  i < n ;
  ++ i ) ans += ( i + 1 ) * ( n - i - 1 ) ;
  return ans ;
}

static long findF_N ( long n ) { long ans = 0 ; for ( long i = 0 ; i < n ; ++ i ) ans += ( i + 1 ) * ( n - i - 1 ) ; return ans ; }
(method_declaration (modifiers) type: (integral_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier))) body: (block (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: (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (decimal_integer_literal))))))) (return_statement (identifier))))