import sys import math sys.setrecursionlimit(10**7) class segki(): DEFAULT = { 'min': 1 << 60, 'max': -(1 << 60), 'sum': 0, 'prd': 1, 'gcd': 0, 'lmc': 1, '^': 0, '&': (1 << 60) - 1, '|': 0, } FUNC = { 'min': min, 'max': max, 'sum': (lambda x, y: x + y), 'prd': (lambda x, y: x * y), 'gcd': math.gcd, 'lmc': (lambda x, y: (x * y) // math.gcd(x, y)), '^': (lambda x, y: x ^ y), '&': (lambda x, y: x & y), '|': (lambda x, y: x | y), } def __init__(self, N, ls, mode='min'): """ 葉の数N, 要素ls, 関数mode (min,max,sum,prd(product),gcd,lmc,^,&,|) """ self.default = self.DEFAULT[mode] self.func = self.FUNC[mode] self.N = N self.K = (N - 1).bit_length() self.N2 = 1 << self.K self.dat = [self.default] * (2**(self.K + 1)) for i in range(self.N): # 葉の構築 self.dat[self.N2 + i] = ls[i] self.build() def build(self): for j in range(self.N2 - 1, -1, -1): self.dat[j] = self.func(self.dat[j << 1], self.dat[j << 1 | 1]) # 親が持つ条件 def leafvalue(self, x): # リストのx番目の値 return self.dat[x + self.N2] def update(self, x, y): # index(x)をyに変更 i = x + self.N2 self.dat[i] = y while i > 0: # 親の値を変更 i >>= 1 self.dat[i] = self.func(self.dat[i << 1], self.dat[i << 1 | 1]) return def query(self, L, R): # [L,R)の区間取得 L += self.N2 R += self.N2 vL = self.default vR = self.default while L < R: if L & 1: vL = self.func(vL, self.dat[L]) L += 1 if R & 1: R -= 1 vR = self.func(self.dat[R], vR) L >>= 1 R >>= 1 return self.func(vL, vR) def iimoji(snum): for k in range(len(snum)-1): if snum[k] > snum[k+1]: return False return True N = int(input()) alpha = list('abcdefghijklmnopqrstuvwxyz') Sall = [input() for i in range(N)] sall = [] for i in range(N): S = Sall[i] Snum = [] for j in range(len(S)): Snum.append(alpha.index(S[j])) if iimoji(Snum): sall.append(Snum) sall.sort(key=lambda x:x[-1]) sall.sort(key=lambda x:x[0]) SG = segki(27,[0]*27,mode='max') for i in range(len(sall)): S = sall[i] v = SG.query(0,S[0]+1) SG.update(S[-1],v+len(S)) print(SG.query(0,27))