An organic compound is synthesised from starting material P\text{P}P via intermediates Q\text{Q}Q and R\text{R}R in a three-stage pathway:
P→Q(75% yield) \text{P} \rightarrow \text{Q} \quad (75\% \text{ yield}) P→Q(75% yield) Q→R(60% yield) \text{Q} \rightarrow \text{R} \quad (60\% \text{ yield}) Q→R(60% yield) R→S(80% yield) \text{R} \rightarrow \text{S} \quad (80\% \text{ yield}) R→S(80% yield)What is the overall percentage yield of compound S\text{S}S from starting material P\text{P}P?
15%15\%15%
36%36\%36%
45%45\%45%
72%72\%72%