输入算法：R%27FR%27B2RF%27R%27B2R2
转换算法：R2 F R2 B2 R F2 R2 B2 R2
R2
180
F
R2
180
B2
180
R
F2
180
R2
180
B2
180
R2
180
180
180
180180180180180180180180180180180180