import sequtils template times*(n:int,body) = (for _ in 0.." .} proc scan(): int = while true: let k = getchar_unlocked() if k < '0': return result = 10 * result + k.ord - '0'.ord let n = scan() var E = newSeqWith(n,newSeq[int]()) (n-1).times: E[scan()-1] &= scan()-1 var preHasCutDP = newSeqWith(n,-1) var preHasNotCutDP = newSeqWith(n,-1) # var time = 0 proc solve(preHasCut:bool,x:int):int = if E[x].len == 0 : return if preHasCut: 1 else: 0 if preHasCut and preHasCutDP[x] != -1 : return preHasCutDP[x] if not preHasCut and preHasNotCutDP[x] != -1 : return preHasNotCutDP[x] # time += 1 var whenCut = 0 for e in E[x]: whenCut += solve(true,e) var whenNotCut = 0 for e in E[x]: whenNotCut += solve(false,e) if preHasCut : whenNotCut += 1 result = max(whenCut,whenNotCut) if preHasCut:preHasCutDP[x] = result else: preHasNotCutDP[x] = result echo solve(true,0) # echo time