manaos friend send new song he listen right away instead compile playlist when feel mind open new music open playlist start listen songsOf course song Manao do not particuarly enjoy to pleasure receive song invent follow procedure listening playlist if listen song Manao realize like remember start listen unlistened song if listening song Manao realize like listen song like point begins listen unlistened song for example Manao song playlist a b c d correspond order go like song a C end order listening follow Manao listen a like remember Manao listen b like listen a Manao listen C like song remember Manao listen D enjoy relisten song a c that end Manao listen song a time song C twice song b D note Manao like song dislike subsequent listeningManao receive n song ith li seconds long Manao like probability pi percent the song Manaos playlist order Manao want know maximum expect value number second listening process possible permutation song playlist