Buggy python submission (verdict: Runtime Error):
from itertools import permutation
N,M=map(int,input().split())
ab=[list(map(int,input().split())) for i in range(M)]
g=[[False]*N for i in range(N)]
for a,b in ab:
  g[a-1][b-1]=True
  g[b-1][a-1]=True
nodes=[i for i in range(N)]
ans=0
for route in permutation(nodes):
  for i in range(N):
    if i == N-1:
      ans+=1
      break
    if g[route[i]][route[i+1]]:
      continue
    else:
      break
print(ans)
      
    
    

Fixed submission:
from itertools import permutations
N,M=map(int,input().split())
ab=[list(map(int,input().split())) for i in range(M)]
g=[[False]*N for i in range(N)]
for a,b in ab:
  g[a-1][b-1]=True
  g[b-1][a-1]=True
nodes=[i for i in range(1,N)]
ans=0
for route in permutations(nodes):
  if g[0][route[0]]== False:
    continue
  for i in range(N-1):
    if i == N-2:
      ans+=1
      
      break
    elif g[route[i]][route[i+1]]:
      continue
    else:
      break
print(ans)

Buggy python submission (verdict: Runtime Error):
N,M=map(int,input().split())
ab=[[0]*8]*8
a=[0]*M
b=[0]*M

reached=[0]*M

for i in range(M):
  a[i],b[i]=map(int,input().split())
  ab[a[i]-1][b[i]-1]=1
  ab[b[i]-1][a[i]-1]=1
    
def rootCount(pos,N,reached):
  count=0
  prev=0
  finish=1
  for i in range(N):
    if reached[i] == 0:
      finish=0
  if finish==1:
    return 1
    
  
  for i in range(1,N):
    if ab[pos][i]==0:
      continue
    if reached[i]==1:
      continue
    reached[i]=1
    count+=rootCount(i,N,reached)
    reached[i]=0
  return(count)

reached[0]=1
count=rootCount(0,N,reached)
print(count)


Fixed submission:
from itertools import permutations
N,M=map(int,input().split())
ab=[list(map(int,input().split())) for i in range(M)]
g=[[False]*N for i in range(N)]
for a,b in ab:
  g[a-1][b-1]=True
  g[b-1][a-1]=True
nodes=[i for i in range(1,N)]
ans=0
for route in permutations(nodes):
  if g[0][route[0]]== False:
    continue
  for i in range(N-1):
    if i == N-2:
      ans+=1
      
      break
    elif g[route[i]][route[i+1]]:
      continue
    else:
      break
print(ans)

Buggy python submission (verdict: Runtime Error):
N,M=map(int,input().split())
ab=[[0]*8]*8
a=[0]*M
b=[0]*M

reached=[0]*M

for i in range(M):
  a[i],b[i]=map(int,input().split())
  ab[a[i]-1][b[i]-1]=1
  ab[b[i]-1][a[i]-1]=1
    
def rootCount(pos,N,reached):
  count=0
  prev=0
  finish=1
  for i in range(N):
    if reached[i] == 0:
      finish=0
  if finish==1:
    return 1
    
  
  for i in range(N):
    if ab[pos][i]==0:
      continue
    if reached[i]==1:
      continue
    reached[i]=1
    count+=rootCount(i,N,reached)
    reached[i]=0
  return(count)

reached[0]=1
count=rootCount(0,N,reached)
print(count)


Fixed submission:
from itertools import permutations
N,M=map(int,input().split())
ab=[list(map(int,input().split())) for i in range(M)]
g=[[False]*N for i in range(N)]
for a,b in ab:
  g[a-1][b-1]=True
  g[b-1][a-1]=True
nodes=[i for i in range(1,N)]
ans=0
for route in permutations(nodes):
  if g[0][route[0]]== False:
    continue
  for i in range(N-1):
    if i == N-2:
      ans+=1
      
      break
    elif g[route[i]][route[i+1]]:
      continue
    else:
      break
print(ans)

Buggy python submission (verdict: Runtime Error):

N,M=map(int,input().split())
ab=[[0]*M]*M
a=[0]*M
b=[0]*M

reached=[0]*M

for i in range(M):
  a[i],b[i]=map(int,input().split())
  ab[a[i]][b[i]]=1
  ab[b[i]][a[i]]=1
    
def rootCount(pos,N,reached):
  count=0
  prev=0
  for i in range(N):
    if ab[pos][i]==0:
      continue
    if reached[i]==1:
      continue
    reached[i]=1
    count+=rootCount(i,N,reached)
    reached[i]=0
  return(count)

reached[0]=1
count=rootCount(0,N,reached)
print(count)

Fixed submission:
from itertools import permutations
N,M=map(int,input().split())
ab=[list(map(int,input().split())) for i in range(M)]
g=[[False]*N for i in range(N)]
for a,b in ab:
  g[a-1][b-1]=True
  g[b-1][a-1]=True
nodes=[i for i in range(1,N)]
ans=0
for route in permutations(nodes):
  if g[0][route[0]]== False:
    continue
  for i in range(N-1):
    if i == N-2:
      ans+=1
      
      break
    elif g[route[i]][route[i+1]]:
      continue
    else:
      break
print(ans)