Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
n=int(input())
lis=[[] for i in range(n*(n-1)//2)]
num=[-1]*(n**2)
cnt=-1
for x in range(n**2):
	if x//n<x%n:
		cnt+=1
		num[x]=cnt
for i in range(n):
	a=list(map(int,input().split()))
	for j in range(n-2):
		x=a[j]-1
		y=a[j+1]-1
		px=num[min(i*n+x,x*n+i)]
		py=num[min(i*n+y,y*n+i)]
		lis[px].append(py)
node_in=[0]*(n*(n-1)//2)
for i in range(n*(n-1)//2):
	for x in lis[i]:
		node_in[x]+=1
zero=deque([])
days=[10**9]*(n*(n-1)//2)
for i in range(n*(n-1)//2):
	if node_in[i]==0:
		zero.append(i)
		days[i]=1
while zero:
	r=zero.popleft()
	for x in lis[r]:
		node_in[x]-=1
		if node_in[x]==0:
			zero.append(x)
			days[x]=days[r]+1
if any([x==10**9 for x in days]):
	print(-1)
else:
	print(max(days))


Fixed submission:
def main():
	from collections import deque
	n=int(input())
	battle=n*(n-1)//2
	lis=[[] for i in range(battle)]
	num=[-1]*(n**2)
	cnt=-1
	for x in range(n**2):
		if x//n<x%n:
			cnt+=1
			num[x]=cnt
	for i in range(n):
		a=list(map(int,input().split()))
		for j in range(n-2):
			x=a[j]-1
			y=a[j+1]-1
			px=num[min(i*n+x,x*n+i)]
			py=num[min(i*n+y,y*n+i)]
			lis[px].append(py)
	node_in=[0]*(battle)
	for i in range(battle):
		for x in lis[i]:
			node_in[x]+=1
	zero=deque([])
	days=[10**9]*(battle)
	for i in range(battle):
		if node_in[i]==0:
			zero.append(i)
			days[i]=1
	while zero:
		r=zero.popleft()
		for x in lis[r]:
			node_in[x]-=1
			if node_in[x]==0:
				zero.append(x)
				days[x]=days[r]+1
	if 10**9 in days:
		print(-1)
	else:
		print(max(days))
if __name__ == '__main__':
	main()

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
n=int(input())
lis=[[] for i in range(n*(n-1)//2)]
num=[-1]*(n**2)
cnt=-1
for x in range(n**2):
	if x//n<x%n:
		cnt+=1
		num[x]=cnt
for i in range(n):
	a=list(map(int,input().split()))
	for j in range(n-2):
		x=a[j]-1
		y=a[j+1]-1
		px=num[min(i*n+x,x*n+i)]
		py=num[min(i*n+y,y*n+i)]
		lis[px].append(py)
node_in=[0]*(n*(n-1)//2)
for i in range(n*(n-1)//2):
	for x in lis[i]:
		node_in[x]+=1
zero=deque([])
days=[10**9]*(n*(n-1)//2)
for i in range(n*(n-1)//2):
	if node_in[i]==0:
		zero.append(i)
		days[i]=1
while zero:
	r=zero.popleft()
	for x in lis[r]:
		node_in[x]-=1
		if node_in[x]==0:
			zero.append(x)
			days[x]=days[r]+1
if any([x==10**9 for x in days]):
	print(-1)
else:
	print(max(days))


Fixed submission:
def main():
	from collections import deque
	n=int(input())
	battle=n*(n-1)//2
	lis=[[] for i in range(battle)]
	num=[-1]*(n**2)
	cnt=-1
	for x in range(n**2):
		if x//n<x%n:
			cnt+=1
			num[x]=cnt
	for i in range(n):
		a=list(map(int,input().split()))
		for j in range(n-2):
			x=a[j]-1
			y=a[j+1]-1
			px=num[min(i*n+x,x*n+i)]
			py=num[min(i*n+y,y*n+i)]
			lis[px].append(py)
	node_in=[0]*(battle)
	for i in range(battle):
		for x in lis[i]:
			node_in[x]+=1
	zero=deque([])
	days=[10**9]*(battle)
	for i in range(battle):
		if node_in[i]==0:
			zero.append(i)
			days[i]=1
	while zero:
		r=zero.popleft()
		for x in lis[r]:
			node_in[x]-=1
			if node_in[x]==0:
				zero.append(x)
				days[x]=days[r]+1
	if 10**9 in days:
		print(-1)
	else:
		print(max(days))
if __name__ == '__main__':
	main()

Buggy python submission (verdict: Time Limit Exceeded):
n=int(input())
a=[]
for i in range(n):
	a.append(list(map(int,input().split())))
d=[[]for _ in range(n**2)]
start=[0]*(n**2)
for i in range(n):
	for j in range(n-2):
		p=[i,a[i][j]-1];q=[i,a[i][j+1]-1]
		if i>a[i][j]-1:
			p=[a[i][j]-1,i]
		if i>a[i][j+1]-1:
			q=[a[i][j+1]-1,i]
		start[p[0]*n+p[1]]+=1
		start[q[0]*n+q[1]]=-10**7
		d[p[0]*n+p[1]].append(q[0]*n+q[1])
st=-1
for i in range(n**2):
	if start[i]>0:
		st=i
		break
if st==-1:
	print(-1)
	exit()
from collections import deque
queue=deque([st])
deep=[1]*(n**2)
while queue:
	p=queue.popleft()
	for x in d[p]:
		queue.append(x)
		deep[x]=deep[p]+1
print(max(deep))

Fixed submission:
def main():
	from collections import deque
	n=int(input())
	battle=n*(n-1)//2
	lis=[[] for i in range(battle)]
	num=[-1]*(n**2)
	cnt=-1
	for x in range(n**2):
		if x//n<x%n:
			cnt+=1
			num[x]=cnt
	for i in range(n):
		a=list(map(int,input().split()))
		for j in range(n-2):
			x=a[j]-1
			y=a[j+1]-1
			px=num[min(i*n+x,x*n+i)]
			py=num[min(i*n+y,y*n+i)]
			lis[px].append(py)
	node_in=[0]*(battle)
	for i in range(battle):
		for x in lis[i]:
			node_in[x]+=1
	zero=deque([])
	days=[10**9]*(battle)
	for i in range(battle):
		if node_in[i]==0:
			zero.append(i)
			days[i]=1
	while zero:
		r=zero.popleft()
		for x in lis[r]:
			node_in[x]-=1
			if node_in[x]==0:
				zero.append(x)
				days[x]=days[r]+1
	if 10**9 in days:
		print(-1)
	else:
		print(max(days))
if __name__ == '__main__':
	main()

Buggy python submission (verdict: Time Limit Exceeded):
n=int(input())
a=[]
for i in range(n):
	a.append(list(map(int,input().split())))
d=[[]for _ in range(n**2)]
start=[0]*(n**2)
for i in range(n):
	for j in range(n-2):
		p=[i,a[i][j]-1];q=[i,a[i][j+1]-1]
		if i>a[i][j]-1:
			p=[a[i][j]-1,i]
		if i>a[i][j+1]-1:
			q=[a[i][j+1]-1,i]
		start[p[0]*n+p[1]]+=1
		start[q[0]*n+q[1]]=-10**7
		d[p[0]*n+p[1]].append(q[0]*n+q[1])
st=-1
for i in range(n**2):
	if start[i]>0:
		st=i
		break
if st==-1:
	print(-1)
	exit()
from collections import deque
stack=deque([st])
deep=[1]*(n**2)
while stack:
	p=stack.pop()
	for x in d[p]:
		stack.append(x)
		deep[x]=deep[p]+1
print(max(deep))

Fixed submission:
def main():
	from collections import deque
	n=int(input())
	battle=n*(n-1)//2
	lis=[[] for i in range(battle)]
	num=[-1]*(n**2)
	cnt=-1
	for x in range(n**2):
		if x//n<x%n:
			cnt+=1
			num[x]=cnt
	for i in range(n):
		a=list(map(int,input().split()))
		for j in range(n-2):
			x=a[j]-1
			y=a[j+1]-1
			px=num[min(i*n+x,x*n+i)]
			py=num[min(i*n+y,y*n+i)]
			lis[px].append(py)
	node_in=[0]*(battle)
	for i in range(battle):
		for x in lis[i]:
			node_in[x]+=1
	zero=deque([])
	days=[10**9]*(battle)
	for i in range(battle):
		if node_in[i]==0:
			zero.append(i)
			days[i]=1
	while zero:
		r=zero.popleft()
		for x in lis[r]:
			node_in[x]-=1
			if node_in[x]==0:
				zero.append(x)
				days[x]=days[r]+1
	if 10**9 in days:
		print(-1)
	else:
		print(max(days))
if __name__ == '__main__':
	main()

Buggy python submission (verdict: Runtime Error):
n=int(input())
a=[]
for i in range(n):
	a.append(list(map(int,input().split())))
d=[[]for _ in range(n**2//2+2)]
start=[0]*(n**2)
for i in range(n):
	for j in range(n-2):
		p=[i,a[i][j]-1];q=[i,a[i][j+1]-1]
		if i>a[i][j]-1:
			p=[a[i][j]-1,i]
		if i>a[i][j+1]-1:
			q=[a[i][j+1]-1,i]
		start[p[0]*n+p[1]]+=1
		start[q[0]*n+q[1]]=-10**7
		d[p[0]*n+p[1]].append(q[0]*n+q[1])
st=-1
for i in range(n**2):
	if start[i]>0:
		st=i
		break
if st==-1:
	print(-1)
	exit()
stack=[st]
deep=[1]*(n**2//2+2)
while stack:
	p=stack.pop()
	for x in d[p]:
		stack.append(x)
		deep[x]=deep[p]+1
print(max(deep))

Fixed submission:
def main():
	from collections import deque
	n=int(input())
	battle=n*(n-1)//2
	lis=[[] for i in range(battle)]
	num=[-1]*(n**2)
	cnt=-1
	for x in range(n**2):
		if x//n<x%n:
			cnt+=1
			num[x]=cnt
	for i in range(n):
		a=list(map(int,input().split()))
		for j in range(n-2):
			x=a[j]-1
			y=a[j+1]-1
			px=num[min(i*n+x,x*n+i)]
			py=num[min(i*n+y,y*n+i)]
			lis[px].append(py)
	node_in=[0]*(battle)
	for i in range(battle):
		for x in lis[i]:
			node_in[x]+=1
	zero=deque([])
	days=[10**9]*(battle)
	for i in range(battle):
		if node_in[i]==0:
			zero.append(i)
			days[i]=1
	while zero:
		r=zero.popleft()
		for x in lis[r]:
			node_in[x]-=1
			if node_in[x]==0:
				zero.append(x)
				days[x]=days[r]+1
	if 10**9 in days:
		print(-1)
	else:
		print(max(days))
if __name__ == '__main__':
	main()

Buggy python submission (verdict: Time Limit Exceeded):
n=int(input())
a=[]
for i in range(n):
	a.append(list(map(int,input().split())))
d=[[]for _ in range(n**2)]
start=[0]*(n**2)
for i in range(n):
	for j in range(n-2):
		p=[i,a[i][j]-1];q=[i,a[i][j+1]-1]
		if i>a[i][j]-1:
			p=[a[i][j]-1,i]
		if i>a[i][j+1]-1:
			q=[a[i][j+1]-1,i]
		start[p[0]*n+p[1]]+=1
		start[q[0]*n+q[1]]=-10**7
		d[p[0]*n+p[1]].append(q[0]*n+q[1])
st=-1
for i in range(n**2):
	if start[i]>0:
		st=i
		break
if st==-1:
	print(-1)
	exit()
stack=[st]
deep=[1]*(n**2)
while stack:
	p=stack.pop()
	for x in d[p]:
		stack.append(x)
		deep[x]=deep[p]+1
print(max(deep))

Fixed submission:
def main():
	from collections import deque
	n=int(input())
	battle=n*(n-1)//2
	lis=[[] for i in range(battle)]
	num=[-1]*(n**2)
	cnt=-1
	for x in range(n**2):
		if x//n<x%n:
			cnt+=1
			num[x]=cnt
	for i in range(n):
		a=list(map(int,input().split()))
		for j in range(n-2):
			x=a[j]-1
			y=a[j+1]-1
			px=num[min(i*n+x,x*n+i)]
			py=num[min(i*n+y,y*n+i)]
			lis[px].append(py)
	node_in=[0]*(battle)
	for i in range(battle):
		for x in lis[i]:
			node_in[x]+=1
	zero=deque([])
	days=[10**9]*(battle)
	for i in range(battle):
		if node_in[i]==0:
			zero.append(i)
			days[i]=1
	while zero:
		r=zero.popleft()
		for x in lis[r]:
			node_in[x]-=1
			if node_in[x]==0:
				zero.append(x)
				days[x]=days[r]+1
	if 10**9 in days:
		print(-1)
	else:
		print(max(days))
if __name__ == '__main__':
	main()

Buggy python submission (verdict: Time Limit Exceeded):
n=int(input())
a=[]
for i in range(n):
	a.append(list(map(int,input().split())))
d=[[]for _ in range(n**2)]
start=[0]*(n**2)
for i in range(n):
	for j in range(n-2):
		p=[i,a[i][j]-1];q=[i,a[i][j+1]-1]
		if i>a[i][j]-1:
			p=[a[i][j]-1,i]
		if i>a[i][j+1]-1:
			q=[a[i][j+1]-1,i]
		start[p[0]*n+p[1]]+=1
		start[q[0]*n+q[1]]=-10**7
		d[p[0]*n+p[1]].append(q[0]*n+q[1])
st=-1
for i in range(n**2):
	if start[i]>0:
		st=i
		break
if st==-1:
	print(-1)
	exit()
stack=[st]
deep=[1]*(n**2)
while stack:
	p=stack.pop()
	for x in d[p]:
		stack.append(x)
		deep[x]=deep[p]+1
print(max(deep))

Fixed submission:
def main():
	from collections import deque
	n=int(input())
	battle=n*(n-1)//2
	lis=[[] for i in range(battle)]
	num=[-1]*(n**2)
	cnt=-1
	for x in range(n**2):
		if x//n<x%n:
			cnt+=1
			num[x]=cnt
	for i in range(n):
		a=list(map(int,input().split()))
		for j in range(n-2):
			x=a[j]-1
			y=a[j+1]-1
			px=num[min(i*n+x,x*n+i)]
			py=num[min(i*n+y,y*n+i)]
			lis[px].append(py)
	node_in=[0]*(battle)
	for i in range(battle):
		for x in lis[i]:
			node_in[x]+=1
	zero=deque([])
	days=[10**9]*(battle)
	for i in range(battle):
		if node_in[i]==0:
			zero.append(i)
			days[i]=1
	while zero:
		r=zero.popleft()
		for x in lis[r]:
			node_in[x]-=1
			if node_in[x]==0:
				zero.append(x)
				days[x]=days[r]+1
	if 10**9 in days:
		print(-1)
	else:
		print(max(days))
if __name__ == '__main__':
	main()