Imaginethatyouareinabuildingthathasexactlynfloors.Youcanmovebetweenthefloorsinalift.Let'snumberthefloorsfrombottomtotopwithintegersfrom1ton.Nowyou'reonthefloornumbera.Youareverybored,soyouwanttotakethelift.Floornumberbhasasecretlab,theentryisforbidden.However,youalreadyareinthemoodanddecidetomakekconsecutivetripsinthelift.Letussupposethatatthemomentyouareonthefloornumberx(initially,youwere...
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