Mike try rock climbing awful there n hold wall ith hold height ai grind besides let sequence ai increase aiai1 1 n1 sequence track Mike think track a1 difficulty in word difficulty equal maximum distance hold adjacent heightToday Mike decide cover track hold hang height a1 to problem hard Mike decide remove hold remove element sequence example sequence 12345 remove element obtain sequence 1245 however Mike awful climbing want final difficulty ie maximum difference height adjacent hold remove hold small possible possible option remove hold the hold stay positionshelp Mike determine minimum difficulty track remove hold