local mfl, mce = math.floor, math.ceil local mmi, mma = math.min, math.max local bls, brs = bit.lshift, bit.rshift local SegTree = {} SegTree.updateAll = function(self) for i = self.stagenum - 1, 1, -1 do local cnt = bls(1, i - 1) for j = 1, cnt do self.stage[i][j] = self.func(self.stage[i + 1][j * 2 - 1], self.stage[i + 1][j * 2]) end end end SegTree.create = function(self, n, func, emptyvalue) self.func, self.emptyvalue = func, emptyvalue local stagenum, mul = 1, 1 self.stage = {{}} while mul < n do mul, stagenum = mul * 2, stagenum + 1 self.stage[stagenum] = {} end self.stagenum = stagenum self.left_stage = {} for i = 1, n do local sp, sz = 1, bls(1, stagenum - 1) while(i - 1) % sz ~= 0 do sp, sz = sp + 1, brs(sz, 1) end self.left_stage[i] = sp end self.sz_stage = {} local tmp, sp = 1, stagenum for i = 1, n do if tmp * 2 == i then tmp, sp = tmp * 2, sp - 1 end self.sz_stage[i] = sp end for i = 1, mul do self.stage[stagenum][i] = emptyvalue end self:updateAll() end SegTree.getRange = function(self, left, right) if left == right then return self.stage[self.stagenum][left] end local stagenum = self.stagenum local ret = self.emptyvalue while left <= right do local stage = mma(self.left_stage[left], self.sz_stage[right - left + 1]) local sz = bls(1, stagenum - stage) ret = self.func(ret, self.stage[stage][1 + brs(left - 1, stagenum - stage)]) left = left + sz end return ret end SegTree.update = function(self, idx) for i = self.stagenum - 1, 1, -1 do local dst = brs(idx + 1, 1) local rem = dst * 4 - 1 - idx self.stage[i][dst] = self.func(self.stage[i + 1][idx], self.stage[i + 1][rem]) idx = dst end end SegTree.setValue = function(self, idx, value, silent) self.stage[self.stagenum][idx] = value if not silent then self:update(idx) end end SegTree.new = function(n, func, emptyvalue) local obj = {} setmetatable(obj, {__index = SegTree}) obj:create(n, func, emptyvalue) return obj end local function SA_IS(data, data_size, word_size) local suffix_array = {} local type_tag = {} -- -2: L, -1: S, 1~: i-th LMS for i = 1, data_size do suffix_array[i] = -1 type_tag[i] = -2 end local word_count = {} local word_count_sum = {} local word_pushback_count = {} local word_pushfront_count = {} for i = 1, word_size do word_count[i] = 0 word_count_sum[i] = 0 word_pushback_count[i] = 0 word_pushfront_count[i] = 0 end local lms_count = 0 local lms_data_indexes = {} local sorted_lms_data_indexes = {} local lms_compressed_data = {} for i = 1, data_size do word_count[data[i]] = word_count[data[i]] + 1 end word_count_sum[1] = word_count[1] for i = 2, word_size do word_count_sum[i] = word_count_sum[i - 1] + word_count[i] end local prev_type = -2 for i = data_size - 1, 1, -1 do if data[i] == data[i + 1] then type_tag[i] = prev_type else type_tag[i] = data[i] < data[i + 1] and -1 or -2 prev_type = type_tag[i] end end for i = 2, data_size do if type_tag[i - 1] == -2 and type_tag[i] == -1 then lms_count = lms_count + 1 type_tag[i] = lms_count lms_data_indexes[lms_count] = i sorted_lms_data_indexes[lms_count] = -1 lms_compressed_data[lms_count] = -1 end end -- put LMS for i = 1, lms_count do local idx = lms_data_indexes[i] local w = data[idx] suffix_array[word_count_sum[w] - word_pushback_count[w]] = idx word_pushback_count[w] = word_pushback_count[w] + 1 end -- put L do local w = data[data_size] local offset = w == 1 and 0 or word_count_sum[w - 1] suffix_array[offset + 1] = data_size word_pushfront_count[w] = word_pushfront_count[w] + 1 end for sufa_idx = 1, data_size - 1 do local data_idx = suffix_array[sufa_idx] if 1 < data_idx then data_idx = data_idx - 1 if type_tag[data_idx] == -2 then local w = data[data_idx] local offset = w == 1 and 0 or word_count_sum[w - 1] word_pushfront_count[w] = word_pushfront_count[w] + 1 suffix_array[offset + word_pushfront_count[w]] = data_idx end end end -- remove LMS for w = 1, word_size do word_pushback_count[w] = 0 end -- put S for sufa_idx = data_size, 1, -1 do local data_idx = suffix_array[sufa_idx] if 1 < data_idx then data_idx = data_idx - 1 if -1 <= type_tag[data_idx] then local w = data[data_idx] suffix_array[word_count_sum[w] - word_pushback_count[w]] = data_idx word_pushback_count[w] = word_pushback_count[w] + 1 end end end local lms_data_value = 0 local prev_lms_index = 0 local prev_lms_data_index = 0 for sufa_idx = 1, data_size do local data_idx = suffix_array[sufa_idx] local lms_idx = type_tag[data_idx] if 1 <= lms_idx then local is_same = false if 0 < prev_lms_data_index and prev_lms_index ~= lms_count and lms_idx ~= lms_count then local len1 = lms_data_indexes[lms_idx + 1] - data_idx local len2 = lms_data_indexes[prev_lms_index + 1] - prev_lms_data_index if len1 == len2 then is_same = true for i = 0, len1 do if data[i + data_idx] ~= data[i + prev_lms_data_index] then is_same = false break end end end end if not is_same then lms_data_value = lms_data_value + 1 end lms_compressed_data[lms_idx] = lms_data_value prev_lms_index = lms_idx prev_lms_data_index = data_idx end end if lms_data_value == lms_count then for i = 1, lms_count do sorted_lms_data_indexes[lms_compressed_data[i]] = lms_data_indexes[i] end else local lms_sa = SA_IS(lms_compressed_data, lms_count, lms_data_value) for i = 1, lms_count do sorted_lms_data_indexes[i] = lms_data_indexes[lms_sa[i]] end end for i = 1, lms_count do local inv = lms_count + 1 - i if inv <= i then break end sorted_lms_data_indexes[i], sorted_lms_data_indexes[inv] = sorted_lms_data_indexes[inv], sorted_lms_data_indexes[i] end -- Second Induced Sort for i = 1, data_size do suffix_array[i] = -1 end for i = 1, word_size do word_pushback_count[i] = 0 word_pushfront_count[i] = 0 end -- put LMS for i = 1, lms_count do local idx = sorted_lms_data_indexes[i] local w = data[idx] suffix_array[word_count_sum[w] - word_pushback_count[w]] = idx word_pushback_count[w] = word_pushback_count[w] + 1 end -- put L do local w = data[data_size] local offset = w == 1 and 0 or word_count_sum[w - 1] suffix_array[offset + 1] = data_size word_pushfront_count[w] = word_pushfront_count[w] + 1 end for sufa_idx = 1, data_size - 1 do local data_idx = suffix_array[sufa_idx] if 1 < data_idx then data_idx = data_idx - 1 if type_tag[data_idx] == -2 then local w = data[data_idx] local offset = w == 1 and 0 or word_count_sum[w - 1] word_pushfront_count[w] = word_pushfront_count[w] + 1 suffix_array[offset + word_pushfront_count[w]] = data_idx end end end -- remove LMS for w = 1, word_size do word_pushback_count[w] = 0 end -- put S for sufa_idx = data_size, 1, -1 do local data_idx = suffix_array[sufa_idx] if 1 < data_idx then data_idx = data_idx - 1 if -1 <= type_tag[data_idx] then local w = data[data_idx] suffix_array[word_count_sum[w] - word_pushback_count[w]] = data_idx word_pushback_count[w] = word_pushback_count[w] + 1 end end end return suffix_array end local SAIS = {} SAIS.create = function(self, data, data_size, word_size) local sufa = SA_IS(data, data_size, word_size) local sufa_inv = {} for i = 1, data_size do sufa_inv[i] = 0 end for i = 1, data_size do sufa_inv[sufa[i]] = i end self.sufa = sufa self.sufa_inv = sufa_inv -- LCPA local n = data_size local lcpa = {} for i = 1, n - 1 do lcpa[i] = 0 end local spos = 0 for i = 1, n do local lcppos = sufa_inv[i] if lcppos < n then local len = spos local p1, p2 = sufa[lcppos], sufa[lcppos + 1] p1, p2 = p1 + spos, p2 + spos while p1 <= n and p2 <= n do if data[p1] == data[p2] then len = len + 1 p1, p2 = p1 + 1, p2 + 1 else break end end lcpa[lcppos] = len spos = 1 < len and len - 1 or 0 end end self.lcpa = lcpa self.data = data self.n = n end local function tblcomp(a, b, bspos) -- return a <= b:sub(bspos, #b) local lim = mmi(#a, #b - bspos + 1) for i = 1, lim do if a[i] ~= b[bspos + i - 1] then return a[i] < b[bspos + i - 1] and true or false end end return #a <= #b - bspos + 1 end --experimental SAIS.lowerBound = function(self, s) if tblcomp(s, self.data, self.sufa[1]) then return 1 end if not tblcomp(s, self.data, self.sufa[self.n]) then return self.n + 1 end local min, max = 1, self.n while 1 < max - min do local mid = mfl((min + max) / 2) if tblcomp(s, self.data, self.sufa[mid]) then max = mid else min = mid end end return max end local s = io.read() local n = #s local t = {} for i = 1, n do t[i] = s:byte(i) - 96 end for i = n, 1, -1 do table.insert(t, t[i]) end SAIS:create(t, n * 2, 26) local sufa = SAIS.sufa local sufa_inv = SAIS.sufa_inv local lcpa = SAIS.lcpa local st = SegTree.new(2 * n - 1, mmi, 1000000007) for i = 1, 2 * n - 1 do st:setValue(i, lcpa[i], true) end st:updateAll() local edge = {} for i = 1, n do edge[i] = {} end for i = 1, n do local j = n * 2 + 1 - i local p1 = sufa_inv[i] local p2 = sufa_inv[j] if p2 < p1 then p1, p2 = p2, p1 end local len = st:getRange(p1, p2 - 1) len = mmi(len, n + 1 - i, i) for j = 1, len do table.insert(edge[i + 1 - j], i + j) end end for i = 2, n do local j = n * 2 + 1 - (i - 1) local p1 = sufa_inv[i] local p2 = sufa_inv[j] if p2 < p1 then p1, p2 = p2, p1 end local len = st:getRange(p1, p2 - 1) len = mmi(len, n + 1 - i, i - 1) for j = 1, len do table.insert(edge[i - j], i + j) end end local a = {} local inf = 1000000007 for i = 1, n + 1 do a[i] = 0 end a[1] = inf for i = 1, n do for j = 1, #edge[i] do local dst = edge[i][j] local len = dst - i a[dst] = mma(a[dst], mmi(a[i], len)) end end print(a[n + 1])