Buggy python submission (verdict: Runtime Error):
#from collections import deque,defaultdict
printn = lambda x: print(x,end='')
inn = lambda : int(input())
inl   = lambda: list(map(int, input().split()))
inm   = lambda:      map(int, input().split())
ins = lambda : input().strip()
DBG = True # and False
BIG = 10**18
R = 10**9 + 7
#R = 998244353

def ddprint(x):
  if DBG:
    print(x)

import sys,resource
def setrlim():
  sys.setrecursionlimit(250000)
  soft,hard = resource.getrlimit(resource.RLIMIT_STACK)
  # setrlimit works on ubuntu (and atcoder), but not on WSL
  resource.setrlimit(resource.RLIMIT_STACK, (128*1024*1024,hard))

def dfs(l,k):
    global ans
    #ddprint(f"dfs {k=} {l=} - - - -")
    ll = [[] for i in range(26)]
    x = [0]*26
    for z in l:
        #ddprint(f"lsz {ls[z]} {z=} {k=}")
        c = ord(ls[z][-k-1])-orda
        if len(ls[z])==k+1:
            x[c] += 1
        else:
            ll[c].append(z)
    #ddprint(f"{x=} {ll=}")
    for c in range(26):
        for z in l:
            #if len(ls)==2:
            #    ddprint(f" z1 {z[1]} {k=} {c=} fst {first[z[1]][c]}")
            if first[z][c]>=k and len(ls[z])>k+1:
                ans += x[c]
                #if x[c]>0:
                #    ddprint(f"ans += {x[c]}")
    for c in range(26):
        if len(ll[c])>0:
            dfs(ll[c],k+1)

setrlim()
n = inn()
ls = []
first = [[-1]*26 for i in range(n)]
orda = ord('a')
for i in range(n):
    s = ins()
    ls.append(s)
    for c in range(26):
        p = s.find(chr(orda+c))
        first[i][c] = (len(s)-1-p) if p>=0 else -1
#ddprint(f"{ls=}")
#ddprint(f"{first=}")
ans = 0
dfs(list(range(n)),0)
print(ans)


Fixed submission:
inn = lambda : int(input())
ins = lambda : input().strip()
DBG = True # and False

def ddprint(x):
  if DBG:
    print(x)

import sys,resource
def setrlim():
  sys.setrecursionlimit(250000)
  soft,hard = resource.getrlimit(resource.RLIMIT_STACK)
  # setrlimit works on ubuntu (and atcoder), but not on WSL
  resource.setrlimit(resource.RLIMIT_STACK, (128*1024*1024,hard))

def dfs(l,k):
    global ans
    #ddprint(f"dfs {k=} {l=} - - - -")
    ll = [[] for i in range(26)]
    x = [0]*26
    for z in l:
        #ddprint(f"lsz {ls[z]} {z=} {k=}")
        c = ord(ls[z][-k-1])-orda
        if len(ls[z])==k+1:
            x[c] += 1
        else:
            ll[c].append(z)
    #ddprint(f"{x=} {ll=}")
    for c in range(26):
        for z in l:
            #if len(ls)==2:
            #    ddprint(f" z1 {z[1]} {k=} {c=} fst {first[z[1]][c]}")
            if first[z][c]>=k and len(ls[z])>k+1:
                ans += x[c]
                #if x[c]>0:
                #    ddprint(f"ans += {x[c]}")
    for c in range(26):
        if len(ll[c])>1:
            dfs(ll[c],k+1)

setrlim()
n = inn()
ls = []
first = [[-1]*26 for i in range(n)]
orda = ord('a')
for i in range(n):
    s = ins()
    ls.append(s)
    for c in range(26):
        p = s.find(chr(orda+c))
        first[i][c] = (len(s)-1-p) if p>=0 else -1
#ddprint(f"{ls=}")
#ddprint(f"{first=}")
ans = 0
dfs(list(range(n)),0)
print(ans)

Buggy python submission (verdict: Runtime Error):
#from collections import deque,defaultdict
printn = lambda x: print(x,end='')
inn = lambda : int(input())
inl   = lambda: list(map(int, input().split()))
inm   = lambda:      map(int, input().split())
ins = lambda : input().strip()
DBG = True # and False
BIG = 10**18
R = 10**9 + 7
#R = 998244353

def ddprint(x):
  if DBG:
    print(x)

import sys,resource
def setrlim():
  sys.setrecursionlimit(250000)
  soft,hard = resource.getrlimit(resource.RLIMIT_STACK)
  # setrlimit works on ubuntu (and atcoder), but not on WSL
  resource.setrlimit(resource.RLIMIT_STACK, (128*1024*1024,hard))

def dfs(ls,k):
    global ans
    #ddprint(f"dfs {k=} {ls=} - - - -")
    ll = [[] for i in range(26)]
    x = [0]*26
    for z in ls:
        c = ord(z[0][-1])-orda
        if len(z[0])==1:
            x[c] += 1
        else:
            ll[c].append((z[0][:-1],z[1]))
    #ddprint(f"{x=} {ll=}")
    for c in range(26):
        for z in ls:
            #if len(ls)==2:
            #    ddprint(f" z1 {z[1]} {k=} {c=} fst {first[z[1]][c]}")
            if first[z[1]][c]>=k and len(z[0])>1:
                ans += x[c]
                #if x[c]>0:
                #    ddprint(f"ans += {x[c]}")
    for c in range(26):
        if len(ll[c])>0:
            dfs(ll[c],k+1)

setrlim()
n = inn()
ls = []
first = [[-1]*26 for i in range(n)]
orda = ord('a')
for i in range(n):
    s = ins()
    ls.append((s,i))
    for c in range(26):
        p = s.find(chr(orda+c))
        first[i][c] = (len(s)-1-p) if p>=0 else -1
#ddprint(f"{ls=}")
#ddprint(f"{first=}")
ans = 0
dfs(ls,0)
print(ans)


Fixed submission:
inn = lambda : int(input())
ins = lambda : input().strip()
DBG = True # and False

def ddprint(x):
  if DBG:
    print(x)

import sys,resource
def setrlim():
  sys.setrecursionlimit(250000)
  soft,hard = resource.getrlimit(resource.RLIMIT_STACK)
  # setrlimit works on ubuntu (and atcoder), but not on WSL
  resource.setrlimit(resource.RLIMIT_STACK, (128*1024*1024,hard))

def dfs(l,k):
    global ans
    #ddprint(f"dfs {k=} {l=} - - - -")
    ll = [[] for i in range(26)]
    x = [0]*26
    for z in l:
        #ddprint(f"lsz {ls[z]} {z=} {k=}")
        c = ord(ls[z][-k-1])-orda
        if len(ls[z])==k+1:
            x[c] += 1
        else:
            ll[c].append(z)
    #ddprint(f"{x=} {ll=}")
    for c in range(26):
        for z in l:
            #if len(ls)==2:
            #    ddprint(f" z1 {z[1]} {k=} {c=} fst {first[z[1]][c]}")
            if first[z][c]>=k and len(ls[z])>k+1:
                ans += x[c]
                #if x[c]>0:
                #    ddprint(f"ans += {x[c]}")
    for c in range(26):
        if len(ll[c])>1:
            dfs(ll[c],k+1)

setrlim()
n = inn()
ls = []
first = [[-1]*26 for i in range(n)]
orda = ord('a')
for i in range(n):
    s = ins()
    ls.append(s)
    for c in range(26):
        p = s.find(chr(orda+c))
        first[i][c] = (len(s)-1-p) if p>=0 else -1
#ddprint(f"{ls=}")
#ddprint(f"{first=}")
ans = 0
dfs(list(range(n)),0)
print(ans)