执行以下操作:

(operator)(operation)(amount)

其中运算符交替为x，y，x，y，...(为此使用％运算符)，运算符交替为+，+，-，-，+，+，-，-，+，+. (再次使用％运算符)，金额更改为1,2,3，...

where operator alternates as x,y,x,y,...(use % operator for that), operation alternates as +,+,-,-,+,+,-,-,+,+...(again use % operator for that) and amount changes as 1,2,3,...