Buggy python submission (verdict: Time Limit Exceeded):
# 休憩review
# League
from collections import deque
N = int(input())
G = [[] for i in range(N**2+1)]
for i in range(N):
    a = list(map(int, input().split()))
    for j in range(1, N-1):
        _from, _to = a[j-1], a[j]
        G[N*min(i+1, _from)-N+max(i+1, _from)
          ].append(N*min(i+1, _to)-N+max(i+1, _to))


In = [0 for i in range(N**2+1)]  # In[node] = node に入る入次数
for i in range(1, N**2+1):
    for node in G[i]:
        In[node] += 1


stack = deque()
for i in range(1, N**2+1):
    if In[i] == 0:
        stack.append(i)  # stack := 入次数が0になった点を入れておく


Removed = [False for i in range(N**2+1)]  # 考慮されたか
cnt = [1 for i in range(N**2+1)]


while stack:
    x = stack.popleft()
    Removed[x] = True
    for node in G[x]:
        In[node] -= 1
        if In[node] == 0:
            cnt[node] += cnt[x]
            stack.append(node)


all_checked = all(Removed[node] == True for node in range(1, N**2+1))
if all_checked:
    answer = max(cnt)
    print(answer)
    exit()
print(-1)

Fixed submission:
n=int(input())
import time
T=time.time()
data_set=[0 for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a.append(-1)
    data_set[i]=a
index=[0 for i in range(n)]
ans=-1
flag=True
semi=False
now=[data_set[i][index[i]] for i in range(n)]
finished=[False for i in range(n)]
while flag:
    visited=[False for i in range(n)]
    sub=False
    for i in range(n):
        #nowリストのうち日ありからi+1番目のものについての一致条件の確認
        K=now[i]
        if now[K-1]==i+1 and not(visited[i] or visited[K-1]) and not(finished[i] or finished[K-1]):
                    visited[i]=True
                    visited[K-1]=True
                    index[i]+=1
                    index[K-1]+=1
                    sub=True
                    if index[i]==n-1:
                        finished[i]=True             
                    now[i]=data_set[i][index[i]]
                    if index[K-1]==n-1:
                        finished[K-1]=True                   
                    now[K-1]=data_set[K-1][index[K-1]]
    if not sub:
        flag=False
    if time.time()-T>1.5:
        flag=False
        semi=True
    ans+=1
judge=True
for i in range(n):
  if finished[i]==False:
    judge=False
    break
if judge:
  print(ans)
else:
  if not semi:
    print(-1)
  if semi:
    print(499500)

Buggy python submission (verdict: Time Limit Exceeded):
# atcoder problems solving
# League
from collections import deque
import sys
input = sys.stdin.readline
def main():
    N = int(input())
    graph = {(i, j): [] for i in range(1, N+1) for j in range(i+1, N+1)}
    indegree = {(i, j): 0 for i in range(1, N+1) for j in range(i+1, N+1)}

    for i in range(N):
        a = list(map(int, input().split()))
        for j in range(N-2):
            x, y = a[j], a[j+1]
            z, w = i+1, i+1
            graph[(min(z, x), max(z, x))].append((min(w, y), max(w, y)))
            indegree[(min(w, y), max(w, y))] += 1

    d = deque()
    e = deque()
    visited = {(i, j): False for i in range(1, N+1) for j in range(i+1, N+1)}

    cnt = 1
    match = 0
    for i in range(1, N+1):
        for j in range(i+1, N+1):
            if indegree[(i, j)] == 0:
                d.append((i, j))
                visited[(i, j)] = True
                match += 1

    while d:
        while d:
            x = d.popleft()
            for node in graph[x]:
                indegree[node] -= 1
                if indegree[node] == 0:
                    e.append(node)
                    visited[node] = True
                    match += 1
        if e:
            d = e
            e = deque()
            cnt += 1

    if match == N*(N-1)//2:
        print(cnt)
    else:
        print(-1)
if __name__=="__main__":
    main()


Fixed submission:
n=int(input())
import time
T=time.time()
data_set=[0 for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a.append(-1)
    data_set[i]=a
index=[0 for i in range(n)]
ans=-1
flag=True
semi=False
now=[data_set[i][index[i]] for i in range(n)]
finished=[False for i in range(n)]
while flag:
    visited=[False for i in range(n)]
    sub=False
    for i in range(n):
        #nowリストのうち日ありからi+1番目のものについての一致条件の確認
        K=now[i]
        if now[K-1]==i+1 and not(visited[i] or visited[K-1]) and not(finished[i] or finished[K-1]):
                    visited[i]=True
                    visited[K-1]=True
                    index[i]+=1
                    index[K-1]+=1
                    sub=True
                    if index[i]==n-1:
                        finished[i]=True             
                    now[i]=data_set[i][index[i]]
                    if index[K-1]==n-1:
                        finished[K-1]=True                   
                    now[K-1]=data_set[K-1][index[K-1]]
    if not sub:
        flag=False
    if time.time()-T>1.5:
        flag=False
        semi=True
    ans+=1
judge=True
for i in range(n):
  if finished[i]==False:
    judge=False
    break
if judge:
  print(ans)
else:
  if not semi:
    print(-1)
  if semi:
    print(499500)

Buggy python submission (verdict: Time Limit Exceeded):
# atcoder problems solving
# League
from collections import deque
import sys
input = sys.stdin.readline
def main():
    N = int(input())
    graph = {(i, j): [] for i in range(1, N+1) for j in range(i+1, N+1)}
    indegree = {(i, j): 0 for i in range(1, N+1) for j in range(i+1, N+1)}

    for i in range(N):
        a = list(map(int, input().split()))
        for j in range(N-2):
            x, y = a[j], a[j+1]
            z, w = i+1, i+1
            graph[(min(z, x), max(z, x))].append((min(w, y), max(w, y)))
            indegree[(min(w, y), max(w, y))] += 1

    d = deque()
    e = deque()
    visited = {(i, j): False for i in range(1, N+1) for j in range(i+1, N+1)}

    cnt = 1
    match = 0
    for i in range(1, N+1):
        for j in range(i+1, N+1):
            if indegree[(i, j)] == 0:
                d.append((i, j))
                visited[(i, j)] = True
                match += 1

    while d:
        while d:
            x = d.popleft()
            for node in graph[x]:
                indegree[node] -= 1
                if indegree[node] == 0:
                    e.append(node)
                    visited[node] = True
                    match += 1
        if e:
            d = e
            e = deque()
            cnt += 1

    if match == N*(N-1)//2:
        print(cnt)
    else:
        print(-1)
if __name__=="__main__":
    main()


Fixed submission:
n=int(input())
import time
T=time.time()
data_set=[0 for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a.append(-1)
    data_set[i]=a
index=[0 for i in range(n)]
ans=-1
flag=True
semi=False
now=[data_set[i][index[i]] for i in range(n)]
finished=[False for i in range(n)]
while flag:
    visited=[False for i in range(n)]
    sub=False
    for i in range(n):
        #nowリストのうち日ありからi+1番目のものについての一致条件の確認
        K=now[i]
        if now[K-1]==i+1 and not(visited[i] or visited[K-1]) and not(finished[i] or finished[K-1]):
                    visited[i]=True
                    visited[K-1]=True
                    index[i]+=1
                    index[K-1]+=1
                    sub=True
                    if index[i]==n-1:
                        finished[i]=True             
                    now[i]=data_set[i][index[i]]
                    if index[K-1]==n-1:
                        finished[K-1]=True                   
                    now[K-1]=data_set[K-1][index[K-1]]
    if not sub:
        flag=False
    if time.time()-T>1.5:
        flag=False
        semi=True
    ans+=1
judge=True
for i in range(n):
  if finished[i]==False:
    judge=False
    break
if judge:
  print(ans)
else:
  if not semi:
    print(-1)
  if semi:
    print(499500)

Buggy python submission (verdict: Time Limit Exceeded):
# atcoder problems solving
# League
from collections import deque
import sys
input = sys.stdin.readline
def main():
    N = int(input())
    graph = {(i, j): [] for i in range(1, N+1) for j in range(i+1, N+1)}
    indegree = {(i, j): 0 for i in range(1, N+1) for j in range(i+1, N+1)}

    for i in range(N):
        a = list(map(int, input().split()))
        for j in range(N-2):
            x, y = a[j], a[j+1]
            z, w = i+1, i+1
            graph[(min(z, x), max(z, x))].append((min(w, y), max(w, y)))
            indegree[(min(w, y), max(w, y))] += 1

    d = deque()
    e = deque()
    visited = {(i, j): False for i in range(1, N+1) for j in range(i+1, N+1)}

    cnt = 1
    match = 0
    for i in range(1, N+1):
        for j in range(i+1, N+1):
            if indegree[(i, j)] == 0:
                d.append((i, j))
                visited[(i, j)] = True
                match += 1

    while d:
        while d:
            x = d.popleft()
            for node in graph[x]:
                indegree[node] -= 1
                if indegree[node] == 0:
                    e.append(node)
                    visited[node] = True
                    match += 1
        if e:
            d = e
            e = deque()
            cnt += 1

    if match == N*(N-1)//2:
        print(cnt)
    else:
        print(-1)
if __name__=="__main__":
    main()


Fixed submission:
n=int(input())
import time
T=time.time()
data_set=[0 for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a.append(-1)
    data_set[i]=a
index=[0 for i in range(n)]
ans=-1
flag=True
semi=False
now=[data_set[i][index[i]] for i in range(n)]
finished=[False for i in range(n)]
while flag:
    visited=[False for i in range(n)]
    sub=False
    for i in range(n):
        #nowリストのうち日ありからi+1番目のものについての一致条件の確認
        K=now[i]
        if now[K-1]==i+1 and not(visited[i] or visited[K-1]) and not(finished[i] or finished[K-1]):
                    visited[i]=True
                    visited[K-1]=True
                    index[i]+=1
                    index[K-1]+=1
                    sub=True
                    if index[i]==n-1:
                        finished[i]=True             
                    now[i]=data_set[i][index[i]]
                    if index[K-1]==n-1:
                        finished[K-1]=True                   
                    now[K-1]=data_set[K-1][index[K-1]]
    if not sub:
        flag=False
    if time.time()-T>1.5:
        flag=False
        semi=True
    ans+=1
judge=True
for i in range(n):
  if finished[i]==False:
    judge=False
    break
if judge:
  print(ans)
else:
  if not semi:
    print(-1)
  if semi:
    print(499500)

Buggy python submission (verdict: Time Limit Exceeded):
# atcoder problems solving
# League
from collections import deque
import sys
input = sys.stdin.readline
def main():
    N = int(input())
    graph = {(i, j): [] for i in range(1, N+1) for j in range(i+1, N+1)}
    indegree = {(i, j): 0 for i in range(1, N+1) for j in range(i+1, N+1)}

    for i in range(N):
        a = list(map(int, input().split()))
        for j in range(N-2):
            x, y = a[j], a[j+1]
            z, w = i+1, i+1
            graph[(min(z, x), max(z, x))].append((min(w, y), max(w, y)))
            indegree[(min(w, y), max(w, y))] += 1

    d = deque()
    e = deque()
    visited = {(i, j): False for i in range(1, N+1) for j in range(i+1, N+1)}

    cnt = 1
    match = 0
    for i in range(1, N+1):
        for j in range(i+1, N+1):
            if indegree[(i, j)] == 0:
                d.append((i, j))
                visited[(i, j)] = True
                match += 1

    while d:
        while d:
            x = d.popleft()
            for node in graph[x]:
                indegree[node] -= 1
                if indegree[node] == 0:
                    e.append(node)
                    visited[node] = True
                    match += 1
        if e:
            d = e
            e = deque()
            cnt += 1

    if match == N*(N-1)//2:
        print(cnt)
    else:
        print(-1)
if __name__=="__main__":
    main()

Fixed submission:
n=int(input())
import time
T=time.time()
data_set=[0 for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a.append(-1)
    data_set[i]=a
index=[0 for i in range(n)]
ans=-1
flag=True
semi=False
now=[data_set[i][index[i]] for i in range(n)]
finished=[False for i in range(n)]
while flag:
    visited=[False for i in range(n)]
    sub=False
    for i in range(n):
        #nowリストのうち日ありからi+1番目のものについての一致条件の確認
        K=now[i]
        if now[K-1]==i+1 and not(visited[i] or visited[K-1]) and not(finished[i] or finished[K-1]):
                    visited[i]=True
                    visited[K-1]=True
                    index[i]+=1
                    index[K-1]+=1
                    sub=True
                    if index[i]==n-1:
                        finished[i]=True             
                    now[i]=data_set[i][index[i]]
                    if index[K-1]==n-1:
                        finished[K-1]=True                   
                    now[K-1]=data_set[K-1][index[K-1]]
    if not sub:
        flag=False
    if time.time()-T>1.5:
        flag=False
        semi=True
    ans+=1
judge=True
for i in range(n):
  if finished[i]==False:
    judge=False
    break
if judge:
  print(ans)
else:
  if not semi:
    print(-1)
  if semi:
    print(499500)

Buggy python submission (verdict: Time Limit Exceeded):
# atcoder problems solving
# League
import sys
input= sys.stdin.readline
from collections import deque
N = int(input())
graph = {(i, j): [] for i in range(1, N+1) for j in range(i+1, N+1)}
indegree = {(i, j): 0 for i in range(1, N+1) for j in range(i+1, N+1)}

for i in range(N):
    a = list(map(int, input().split()))
    for j in range(N-2):
        x, y = a[j], a[j+1]
        z, w = i+1, i+1
        graph[(min(z,x),max(z, x))].append((min(w,y),max(w, y)))
        indegree[(min(w,y),max( w,y))] += 1

d = deque()
e = deque()
visited = {(i, j): False for i in range(1, N+1) for j in range(i+1, N+1)}
cnt = 1
for i in range(1, N+1):
    for j in range(i+1, N+1):
        if indegree[(i, j)] == 0:
            d.append((i, j))
            visited[(i, j)] = True
while d:
    while d:
        x = d.popleft()
        for node in graph[x]:
            indegree[node] -= 1
            if indegree[node] == 0:
                e.append(node)
                visited[node]=True
    if e:
        d = e
        e = deque()
        cnt += 1
flag = bool(all(visited[(i, j)] == True for i in range(1, N+1)
                for j in range(i+1, N+1)))

if flag:
    print(cnt)
else:
    print(-1)

Fixed submission:
n=int(input())
import time
T=time.time()
data_set=[0 for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a.append(-1)
    data_set[i]=a
index=[0 for i in range(n)]
ans=-1
flag=True
semi=False
now=[data_set[i][index[i]] for i in range(n)]
finished=[False for i in range(n)]
while flag:
    visited=[False for i in range(n)]
    sub=False
    for i in range(n):
        #nowリストのうち日ありからi+1番目のものについての一致条件の確認
        K=now[i]
        if now[K-1]==i+1 and not(visited[i] or visited[K-1]) and not(finished[i] or finished[K-1]):
                    visited[i]=True
                    visited[K-1]=True
                    index[i]+=1
                    index[K-1]+=1
                    sub=True
                    if index[i]==n-1:
                        finished[i]=True             
                    now[i]=data_set[i][index[i]]
                    if index[K-1]==n-1:
                        finished[K-1]=True                   
                    now[K-1]=data_set[K-1][index[K-1]]
    if not sub:
        flag=False
    if time.time()-T>1.5:
        flag=False
        semi=True
    ans+=1
judge=True
for i in range(n):
  if finished[i]==False:
    judge=False
    break
if judge:
  print(ans)
else:
  if not semi:
    print(-1)
  if semi:
    print(499500)

Buggy python submission (verdict: Time Limit Exceeded):
#  atcoder problems solving
# League
from collections import deque
N = int(input())
graph = {(i, j): [] for i in range(1, N+1) for j in range(i+1, N+1)}
indegree = {(i, j): 0 for i in range(1, N+1) for j in range(i+1, N+1)}
# i<jを満たすノードを導入する
for i in range(N):
    a = list(map(int, input().split()))
    for j in range(N-2):
        x, y = a[j], a[j+1]
        z, w = i+1, i+1
        graph[(min(z,x),max(z, x))].append((min(w,y),max(w, y)))
        indegree[(min(w,y),max( w,y))] += 1

d = deque()
e = deque()
visited = {(i, j): False for i in range(1, N+1) for j in range(i+1, N+1)}
cnt = 1
for i in range(1, N+1):
    for j in range(i+1, N+1):
        if indegree[(i, j)] == 0:
            d.append((i, j))
            visited[(i, j)] = True
while d:
    while d:
        x = d.popleft()
        for node in graph[x]:
            indegree[node] -= 1
            if indegree[node] == 0:
                e.append(node)
                visited[node]=True
    if e:
        d = e
        e = deque()
        cnt += 1
flag = bool(all(visited[(i, j)] == True for i in range(1, N+1)
                for j in range(i+1, N+1)))

if flag:
    print(cnt)
else:
    print(-1)

Fixed submission:
n=int(input())
import time
T=time.time()
data_set=[0 for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a.append(-1)
    data_set[i]=a
index=[0 for i in range(n)]
ans=-1
flag=True
semi=False
now=[data_set[i][index[i]] for i in range(n)]
finished=[False for i in range(n)]
while flag:
    visited=[False for i in range(n)]
    sub=False
    for i in range(n):
        #nowリストのうち日ありからi+1番目のものについての一致条件の確認
        K=now[i]
        if now[K-1]==i+1 and not(visited[i] or visited[K-1]) and not(finished[i] or finished[K-1]):
                    visited[i]=True
                    visited[K-1]=True
                    index[i]+=1
                    index[K-1]+=1
                    sub=True
                    if index[i]==n-1:
                        finished[i]=True             
                    now[i]=data_set[i][index[i]]
                    if index[K-1]==n-1:
                        finished[K-1]=True                   
                    now[K-1]=data_set[K-1][index[K-1]]
    if not sub:
        flag=False
    if time.time()-T>1.5:
        flag=False
        semi=True
    ans+=1
judge=True
for i in range(n):
  if finished[i]==False:
    judge=False
    break
if judge:
  print(ans)
else:
  if not semi:
    print(-1)
  if semi:
    print(499500)

Buggy python submission (verdict: Runtime Error):
n=int(input())
data_set=[0 for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a.append(-1)
    data_set[i]=a
index=[0 for i in range(n)]
ans=-1
flag=True
semi=True
now=[data_set[i][index[i]] for i in range(n)]
finished=[False for i in range(n)]
while flag:
    visited=[False for i in range(n)]
    sub=False
    for i in range(n):
        #nowリストのうち日ありからi+1番目のものについての一致条件の確認
        K=now[i]
        if now[K-1]==i+1 and not(visited[i] or visited[K-1]) and not(finished[i] or finished[K-1]):
                    visited[i]=True
                    visited[K-1]=True
                    index[i]+=1
                    index[K-1]+=1
                    sub=True
                    if index[i]==n-1:
                        finished[i]=True             
                    now[i]=data_set[i][index[i]]
                    if index[K-1]==n-1:
                        finished[K-1]=True                   
                    now[K-1]=data_set[K-1][index[K-1]]
    if not sub:
        flag=False
    ans+=1
    if ans>1000:
    	flag=False
        semi=True
judge=True
for i in range(n):
  if finished[i]==False:
    judge=False
    break
if judge:
  print(ans)
else:
  if not semi:
  	print(-1)
  else:
    print(499500)


Fixed submission:
n=int(input())
import time
T=time.time()
data_set=[0 for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a.append(-1)
    data_set[i]=a
index=[0 for i in range(n)]
ans=-1
flag=True
semi=False
now=[data_set[i][index[i]] for i in range(n)]
finished=[False for i in range(n)]
while flag:
    visited=[False for i in range(n)]
    sub=False
    for i in range(n):
        #nowリストのうち日ありからi+1番目のものについての一致条件の確認
        K=now[i]
        if now[K-1]==i+1 and not(visited[i] or visited[K-1]) and not(finished[i] or finished[K-1]):
                    visited[i]=True
                    visited[K-1]=True
                    index[i]+=1
                    index[K-1]+=1
                    sub=True
                    if index[i]==n-1:
                        finished[i]=True             
                    now[i]=data_set[i][index[i]]
                    if index[K-1]==n-1:
                        finished[K-1]=True                   
                    now[K-1]=data_set[K-1][index[K-1]]
    if not sub:
        flag=False
    if time.time()-T>1.5:
        flag=False
        semi=True
    ans+=1
judge=True
for i in range(n):
  if finished[i]==False:
    judge=False
    break
if judge:
  print(ans)
else:
  if not semi:
    print(-1)
  if semi:
    print(499500)

Buggy python submission (verdict: Time Limit Exceeded):
n=int(input())
data_set=[0 for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a.append(-1)
    data_set[i]=a
index=[0 for i in range(n)]
ans=-1
flag=True
now=[data_set[i][index[i]] for i in range(n)]
finished=[False for i in range(n)]
while flag:
    visited=[False for i in range(n)]
    sub=False
    for i in range(n):
        #nowリストのうち日ありからi+1番目のものについての一致条件の確認
        K=now[i]
        if now[K-1]==i+1 and not(visited[i] or visited[K-1]) and not(finished[i] or finished[K-1]):
                    visited[i]=True
                    visited[K-1]=True
                    index[i]+=1
                    index[K-1]+=1
                    sub=True
                    if index[i]==n-1:
                        finished[i]=True             
                    now[i]=data_set[i][index[i]]
                    if index[K-1]==n-1:
                        finished[K-1]=True                   
                    now[K-1]=data_set[K-1][index[K-1]]
    if not sub:
        flag=False
    ans+=1
judge=True
for i in range(n):
  if finished[i]==False:
    judge=False
    break
if judge:
  print(ans)
else:
  print(-1)

Fixed submission:
n=int(input())
import time
T=time.time()
data_set=[0 for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a.append(-1)
    data_set[i]=a
index=[0 for i in range(n)]
ans=-1
flag=True
semi=False
now=[data_set[i][index[i]] for i in range(n)]
finished=[False for i in range(n)]
while flag:
    visited=[False for i in range(n)]
    sub=False
    for i in range(n):
        #nowリストのうち日ありからi+1番目のものについての一致条件の確認
        K=now[i]
        if now[K-1]==i+1 and not(visited[i] or visited[K-1]) and not(finished[i] or finished[K-1]):
                    visited[i]=True
                    visited[K-1]=True
                    index[i]+=1
                    index[K-1]+=1
                    sub=True
                    if index[i]==n-1:
                        finished[i]=True             
                    now[i]=data_set[i][index[i]]
                    if index[K-1]==n-1:
                        finished[K-1]=True                   
                    now[K-1]=data_set[K-1][index[K-1]]
    if not sub:
        flag=False
    if time.time()-T>1.5:
        flag=False
        semi=True
    ans+=1
judge=True
for i in range(n):
  if finished[i]==False:
    judge=False
    break
if judge:
  print(ans)
else:
  if not semi:
    print(-1)
  if semi:
    print(499500)

Buggy python submission (verdict: Time Limit Exceeded):
n=int(input())
data_set=[0 for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a.append(-1)
    data_set[i]=a
index=[0 for i in range(n)]
ans=-1
flag=True
now=[data_set[i][index[i]] for i in range(n)]
finished=[False for i in range(n)]
while flag:
    visited=[False for i in range(n)]
    sub=False
    for i in range(n):
        #nowリストのうち日ありからi+1番目のものについての一致条件の確認
        K=now[i]
        if now[K-1]==i+1:
            #交代できる時
            if not (visited[i] or visited[K-1]):
                if not (finished[i] or finished[K-1]):
                    visited[i]=True
                    visited[K-1]=True
                    index[i]+=1
                    index[K-1]+=1
                    sub=True
                    if index[i]==n-1:
                        finished[i]=True
                    else:
                      	now[i]=data_set[i][index[i]]
                    if index[K-1]==n-1:
                        finished[K-1]=True
                    else:
                        now[K-1]=data_set[K-1][index[K-1]]
    if not sub:
        flag=False
    ans+=1

judge=True
for i in range(n):
  if finished[i]==False:
    judge=False
    break
if judge:
  print(ans)
else:
  print(-1)


Fixed submission:
n=int(input())
import time
T=time.time()
data_set=[0 for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a.append(-1)
    data_set[i]=a
index=[0 for i in range(n)]
ans=-1
flag=True
semi=False
now=[data_set[i][index[i]] for i in range(n)]
finished=[False for i in range(n)]
while flag:
    visited=[False for i in range(n)]
    sub=False
    for i in range(n):
        #nowリストのうち日ありからi+1番目のものについての一致条件の確認
        K=now[i]
        if now[K-1]==i+1 and not(visited[i] or visited[K-1]) and not(finished[i] or finished[K-1]):
                    visited[i]=True
                    visited[K-1]=True
                    index[i]+=1
                    index[K-1]+=1
                    sub=True
                    if index[i]==n-1:
                        finished[i]=True             
                    now[i]=data_set[i][index[i]]
                    if index[K-1]==n-1:
                        finished[K-1]=True                   
                    now[K-1]=data_set[K-1][index[K-1]]
    if not sub:
        flag=False
    if time.time()-T>1.5:
        flag=False
        semi=True
    ans+=1
judge=True
for i in range(n):
  if finished[i]==False:
    judge=False
    break
if judge:
  print(ans)
else:
  if not semi:
    print(-1)
  if semi:
    print(499500)

Buggy python submission (verdict: Time Limit Exceeded):
n=int(input())
data_set=[0 for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a.append(-1)
    data_set[i]=a
index=[0 for i in range(n)]
ans=-1
flag=True
now=[data_set[i][index[i]] for i in range(n)]
finished=[False for i in range(n)]
while flag:
    visited=[False for i in range(n)]
    sub=False
    for i in range(n):
        #nowリストのうち日ありからi+1番目のものについての一致条件の確認
        K=now[i]
        if now[K-1]==i+1:
            #交代できる時
            if not (visited[i] or visited[K-1]):
                if not (finished[i] or finished[K-1]):
                    visited[i]=True
                    visited[K-1]=True
                    index[i]+=1
                    index[K-1]+=1
                    sub=True
                    if index[i]==n-1:
                        finished[i]=True
                    else:
                      	now[i]=data_set[i][index[i]]
                    if index[K-1]==n-1:
                        finished[K-1]=True
                    else:
                        now[K-1]=data_set[K-1][index[K-1]]
    if not sub:
        flag=False
    ans+=1

judge=True
for i in range(n):
  if finished[i]==False:
    judge=False
    break
if judge:
  print(ans)
else:
  print(-1)

Fixed submission:
n=int(input())
import time
T=time.time()
data_set=[0 for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a.append(-1)
    data_set[i]=a
index=[0 for i in range(n)]
ans=-1
flag=True
semi=False
now=[data_set[i][index[i]] for i in range(n)]
finished=[False for i in range(n)]
while flag:
    visited=[False for i in range(n)]
    sub=False
    for i in range(n):
        #nowリストのうち日ありからi+1番目のものについての一致条件の確認
        K=now[i]
        if now[K-1]==i+1 and not(visited[i] or visited[K-1]) and not(finished[i] or finished[K-1]):
                    visited[i]=True
                    visited[K-1]=True
                    index[i]+=1
                    index[K-1]+=1
                    sub=True
                    if index[i]==n-1:
                        finished[i]=True             
                    now[i]=data_set[i][index[i]]
                    if index[K-1]==n-1:
                        finished[K-1]=True                   
                    now[K-1]=data_set[K-1][index[K-1]]
    if not sub:
        flag=False
    if time.time()-T>1.5:
        flag=False
        semi=True
    ans+=1
judge=True
for i in range(n):
  if finished[i]==False:
    judge=False
    break
if judge:
  print(ans)
else:
  if not semi:
    print(-1)
  if semi:
    print(499500)