import sys readline=sys.stdin.readline class Segment_Tree: def __init__(self,N,f,e,lst=None): self.f=f self.e=e self.N=N if lst==None: self.segment_tree=[self.e]*2*self.N else: assert len(lst)<=self.N self.segment_tree=[self.e]*self.N+[x for x in lst]+[self.e]*(N-len(lst)) for i in range(self.N-1,0,-1): self.segment_tree[i]=self.f(self.segment_tree[i<<1],self.segment_tree[i<<1|1]) def __getitem__(self,i): if type(i)==int: if -self.N<=i<0: return self.segment_tree[i+self.N*2] elif 0<=i1: i>>= 1 self.segment_tree[i]=self.f(self.segment_tree[i<<1],self.segment_tree[i<<1|1]) def Build(self,lst): for i,x in enumerate(lst,self.N): self.segment_tree[i]=x for i in range(self.N-1,0,-1): self.segment_tree[i]=self.f(self.segment_tree[i<<1],self.segment_tree[i<<1|1]) def Fold(self,L=None,R=None): if L==None or L<-self.N: L=self.N elif self.N<=L: L=self.N*2 elif L<0: L+=self.N*2 else: L+=self.N if R==None or self.N<=R: R=self.N*2 elif R<-self.N: R=self.N elif R<0: R+=self.N*2 else: R+=self.N vL=self.e vR=self.e while L>=1 R>>=1 return self.f(vL,vR) def Fold_Index(self,L=None,R=None): if L==None or L<-self.N: L=self.N elif self.N<=L: L=self.N*2 elif L<0: L+=self.N*2 else: L+=self.N if R==None or self.N<=R: R=self.N*2 elif R<-self.N: R=self.N elif R<0: R+=self.N*2 else: R+=self.N if L==R: return None x=self.Fold(L-self.N,R-self.N) while L>=1 R>>=1 while i