static int countPaths ( int n ) {
  int zB = 1 ;
  int zADC = 0 ;
  for ( int i = 1 ;
  i <= n ;
  i ++ ) {
    int nzB = zADC * 3 ;
    int nzADC = ( zADC * 2 + zB ) ;
    zB = nzB ;
    zADC = nzADC ;
  }
  return zB ;
}

static int countPaths ( int n ) { int zB = 1 ; int zADC = 0 ; for ( int i = 1 ; i <= n ; i ++ ) { int nzB = zADC * 3 ; int nzADC = ( zADC * 2 + zB ) ; zB = nzB ; zADC = nzADC ; } return zB ; }
(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))) (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: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (identifier) right: (decimal_integer_literal)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (identifier))))) (expression_statement (assignment_expression left: (identifier) right: (identifier))) (expression_statement (assignment_expression left: (identifier) right: (identifier))))) (return_statement (identifier))))