運算式 3: "p" left parenthesis, 2 , right parenthesisp2
3
運算式 4: "p" left parenthesis, 3 , right parenthesis , "p" left parenthesis, 4 , right parenthesis , "p" left parenthesis, 5 , right parenthesis , "p" left parenthesis, 6 , right parenthesisp3,p4,p5,p6