Buggy python submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-

#############
# Libraries #
#############

import sys
input = sys.stdin.readline

import math
#from math import gcd
import bisect
import heapq
from collections import defaultdict
from collections import deque
from collections import Counter
from functools import lru_cache

#############
# Constants #
#############

MOD = 10**9+7
INF = float('inf')
AZ = "abcdefghijklmnopqrstuvwxyz"

#############
# Functions #
#############

######INPUT######
def I(): return int(input().strip())
def S(): return input().strip()
def IL(): return list(map(int,input().split()))
def SL(): return list(map(str,input().split()))
def ILs(n): return list(int(input()) for _ in range(n))
def SLs(n): return list(input().strip() for _ in range(n))
def ILL(n): return [list(map(int, input().split())) for _ in range(n)]
def SLL(n): return [list(map(str, input().split())) for _ in range(n)]


#####Shorten#####
def DD(arg): return defaultdict(arg)

#############
# Main Code #
#############

N = I()
words = [w[::-1] for w in SLs(N)]
words.sort()
Lsortwords = sorted([(i,words[i]) for i in range(N)],key = lambda x:-len(x[1]))

class SegmentTree:
  def __init__(self, n, op, e):
    self.n = n
    self.op = op
    self.e = e
    self.size = 2 ** ((n - 1).bit_length())
    self.node = [self.e] * (2 * self.size)
 
  def build(self, array):
    for i in range(self.n):
      self.node[self.size + i] = array[i]
    for i in range(self.size - 1, 0, -1):
      self.node[i] = self.op(self.node[i << 1], self.node[(i << 1) + 1])
 
  def update(self, i, val):
    i += self.size
    self.node[i] += val
    while i > 1:
      i >>= 1
      self.node[i] = self.op(self.node[i << 1], self.node[(i << 1) + 1])
 
  def get(self, l, r):
    l, r = l + self.size, r + self.size
    res_l, res_r = self.e, self.e
    while l < r:
      if l & 1:
        res_l = self.op(res_l, self.node[l])
        l += 1
      if r & 1:
        r -= 1
        res_r = self.op(self.node[r], res_r) 
      l, r = l >> 1, r >> 1
    return self.op(res_l, res_r)
  
ST = {l:SegmentTree(N,lambda a,b:a+b,0) for l in AZ}

ans = 0
shori = 0
for i in range(len(Lsortwords[0][1]))[::-1]:
  for j,w in Lsortwords:
    if len(w) <= i :break
    ST[w[i]].update(j,1)
  while shori < N and len(Lsortwords[shori][1]) == i+1:
    w = Lsortwords[shori][1]
    p = w[:-1]
    q = w[-1]
    l = bisect.bisect_left(words,p)
    r = bisect.bisect(words,p+chr(97 + 26))
    ans += ST[q].get(l,r+1)-1
    exit()
    shori += 1
    if shori == N: break
      
print(ans)

Fixed submission:
# -*- coding: utf-8 -*-

#############
# Libraries #
#############

import sys
input = sys.stdin.readline

import math
#from math import gcd
import bisect
import heapq
from collections import defaultdict
from collections import deque
from collections import Counter
from functools import lru_cache

#############
# Constants #
#############

MOD = 10**9+7
INF = float('inf')
AZ = "abcdefghijklmnopqrstuvwxyz"

#############
# Functions #
#############

######INPUT######
def I(): return int(input().strip())
def S(): return input().strip()
def IL(): return list(map(int,input().split()))
def SL(): return list(map(str,input().split()))
def ILs(n): return list(int(input()) for _ in range(n))
def SLs(n): return list(input().strip() for _ in range(n))
def ILL(n): return [list(map(int, input().split())) for _ in range(n)]
def SLL(n): return [list(map(str, input().split())) for _ in range(n)]


#####Shorten#####
def DD(arg): return defaultdict(arg)

#############
# Main Code #
#############

N = I()
words = [w[::-1] for w in SLs(N)]
words.sort()
Lsortwords = sorted([(i,words[i]) for i in range(N)],key = lambda x:-len(x[1]))

class SegmentTree:
  def __init__(self, n, op, e):
    self.n = n
    self.op = op
    self.e = e
    self.size = 2 ** ((n - 1).bit_length())
    self.node = [self.e] * (2 * self.size)
 
  def build(self, array):
    for i in range(self.n):
      self.node[self.size + i] = array[i]
    for i in range(self.size - 1, 0, -1):
      self.node[i] = self.op(self.node[i << 1], self.node[(i << 1) + 1])
 
  def update(self, i, val):
    i += self.size
    self.node[i] += val
    while i > 1:
      i >>= 1
      self.node[i] = self.op(self.node[i << 1], self.node[(i << 1) + 1])
 
  def get(self, l, r):
    l, r = l + self.size, r + self.size
    res_l, res_r = self.e, self.e
    while l < r:
      if l & 1:
        res_l = self.op(res_l, self.node[l])
        l += 1
      if r & 1:
        r -= 1
        res_r = self.op(self.node[r], res_r) 
      l, r = l >> 1, r >> 1
    return self.op(res_l, res_r)
  
ST = {l:SegmentTree(N,lambda a,b:a+b,0) for l in AZ}
check = [DD(int) for i in range(N)]
ans = 0
shori = 0
for i in range(len(Lsortwords[0][1]))[::-1]:
  for j,w in Lsortwords:
    if len(w) <= i: break
    if not check[j][w[i]]:
      ST[w[i]].update(j,1)
      check[j][w[i]] = 1
  while shori < N and len(Lsortwords[shori][1]) == i+1:
    w = Lsortwords[shori][1]
    p = w[:-1]
    q = w[-1]
    l = bisect.bisect_left(words,p)
    r = bisect.bisect(words,p+chr(97 + 26))
    ans += ST[q].get(l,r)-1
    shori += 1
    if shori == N: break
      
print(ans)

Buggy python submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-

#############
# Libraries #
#############

import sys
input = sys.stdin.readline

import math
#from math import gcd
import bisect
import heapq
from collections import defaultdict
from collections import deque
from collections import Counter
from functools import lru_cache

#############
# Constants #
#############

MOD = 10**9+7
INF = float('inf')
AZ = "abcdefghijklmnopqrstuvwxyz"

#############
# Functions #
#############

######INPUT######
def I(): return int(input().strip())
def S(): return input().strip()
def IL(): return list(map(int,input().split()))
def SL(): return list(map(str,input().split()))
def ILs(n): return list(int(input()) for _ in range(n))
def SLs(n): return list(input().strip() for _ in range(n))
def ILL(n): return [list(map(int, input().split())) for _ in range(n)]
def SLL(n): return [list(map(str, input().split())) for _ in range(n)]


#####Shorten#####
def DD(arg): return defaultdict(arg)

#############
# Main Code #
#############

N = I()
words = [w[::-1] for w in SLs(N)]
words.sort()
Lsortwords = sorted([(i,words[i]) for i in range(N)],key = lambda x:-len(x[1]))

class SegmentTree:
  def __init__(self, n, op, e):
    self.n = n
    self.op = op
    self.e = e
    self.size = 2 ** ((n - 1).bit_length())
    self.node = [self.e] * (2 * self.size)
 
  def build(self, array):
    for i in range(self.n):
      self.node[self.size + i] = array[i]
    for i in range(self.size - 1, 0, -1):
      self.node[i] = self.op(self.node[i << 1], self.node[(i << 1) + 1])
 
  def update(self, i, val):
    i += self.size
    self.node[i] += val
    while i > 1:
      i >>= 1
      self.node[i] = self.op(self.node[i << 1], self.node[(i << 1) + 1])
 
  def get(self, l, r):
    l, r = l + self.size, r + self.size
    res_l, res_r = self.e, self.e
    while l < r:
      if l & 1:
        res_l = self.op(res_l, self.node[l])
        l += 1
      if r & 1:
        r -= 1
        res_r = self.op(self.node[r], res_r) 
      l, r = l >> 1, r >> 1
    return self.op(res_l, res_r)
  
ST = {l:SegmentTree(N,lambda a,b:a+b,0) for l in AZ}

ans = 0
shori = 0
for i in range(len(Lsortwords[0][1]))[::-1]:
  for j,w in Lsortwords:
    if len(w) <= i :break
    ST[w[i]].update(j,1)
  while shori < N and len(Lsortwords[shori][1]) == i+1:
    w = Lsortwords[shori][1]
    p = w[:-1]
    q = w[-1]
    l = bisect.bisect_left(words,p)
    r = bisect.bisect(words,p+chr(97 + 26))
    ans += ST[q].get(l,r+1)-1
    shori += 1
    if shori == N: break
      
print(ans)

Fixed submission:
# -*- coding: utf-8 -*-

#############
# Libraries #
#############

import sys
input = sys.stdin.readline

import math
#from math import gcd
import bisect
import heapq
from collections import defaultdict
from collections import deque
from collections import Counter
from functools import lru_cache

#############
# Constants #
#############

MOD = 10**9+7
INF = float('inf')
AZ = "abcdefghijklmnopqrstuvwxyz"

#############
# Functions #
#############

######INPUT######
def I(): return int(input().strip())
def S(): return input().strip()
def IL(): return list(map(int,input().split()))
def SL(): return list(map(str,input().split()))
def ILs(n): return list(int(input()) for _ in range(n))
def SLs(n): return list(input().strip() for _ in range(n))
def ILL(n): return [list(map(int, input().split())) for _ in range(n)]
def SLL(n): return [list(map(str, input().split())) for _ in range(n)]


#####Shorten#####
def DD(arg): return defaultdict(arg)

#############
# Main Code #
#############

N = I()
words = [w[::-1] for w in SLs(N)]
words.sort()
Lsortwords = sorted([(i,words[i]) for i in range(N)],key = lambda x:-len(x[1]))

class SegmentTree:
  def __init__(self, n, op, e):
    self.n = n
    self.op = op
    self.e = e
    self.size = 2 ** ((n - 1).bit_length())
    self.node = [self.e] * (2 * self.size)
 
  def build(self, array):
    for i in range(self.n):
      self.node[self.size + i] = array[i]
    for i in range(self.size - 1, 0, -1):
      self.node[i] = self.op(self.node[i << 1], self.node[(i << 1) + 1])
 
  def update(self, i, val):
    i += self.size
    self.node[i] += val
    while i > 1:
      i >>= 1
      self.node[i] = self.op(self.node[i << 1], self.node[(i << 1) + 1])
 
  def get(self, l, r):
    l, r = l + self.size, r + self.size
    res_l, res_r = self.e, self.e
    while l < r:
      if l & 1:
        res_l = self.op(res_l, self.node[l])
        l += 1
      if r & 1:
        r -= 1
        res_r = self.op(self.node[r], res_r) 
      l, r = l >> 1, r >> 1
    return self.op(res_l, res_r)
  
ST = {l:SegmentTree(N,lambda a,b:a+b,0) for l in AZ}
check = [DD(int) for i in range(N)]
ans = 0
shori = 0
for i in range(len(Lsortwords[0][1]))[::-1]:
  for j,w in Lsortwords:
    if len(w) <= i: break
    if not check[j][w[i]]:
      ST[w[i]].update(j,1)
      check[j][w[i]] = 1
  while shori < N and len(Lsortwords[shori][1]) == i+1:
    w = Lsortwords[shori][1]
    p = w[:-1]
    q = w[-1]
    l = bisect.bisect_left(words,p)
    r = bisect.bisect(words,p+chr(97 + 26))
    ans += ST[q].get(l,r)-1
    shori += 1
    if shori == N: break
      
print(ans)