Buggy python submission (verdict: Time Limit Exceeded):
import sys
import collections
import copy
def input(): return sys.stdin.readline().strip()
N = int(input())
sc = [[int(i) for i in input().split()] for i in range(N)]
count = [0] * N
done = [0] * N
fin = [N-1] * N
ans = 0
chk = 0
for j in range(N*(N-1)//2):
    done = [0] * N
    for i in range(N-1):
        if N-1 > count[i]:
            if done[sc[i][count[i]]-1] == 0 and done[i] == 0:
                if sc[sc[i][count[i]]-1][count[sc[i][count[i]]-1]] == i+1:
                    done[sc[i][count[i]]-1] = 1
                    done[i] = 1
                    count[sc[i][count[i]]-1] += 1
                    count[i] += 1
    if done == [0] * N:
        if count == fin:
            break
        else:
            ans = -1
            break
    ans += 1
print(ans)

Fixed submission:
import sys
import collections
import copy
def input(): return sys.stdin.readline().strip()
N = int(input())
sc = [[int(i) for i in input().split()] for i in range(N)]
count = [0] * N
done = [0] * N
fin = [N-1] * N
ans = 0
chk = 0
for j in range(N*(N-1)//2):
    if j >= 4000:
        chk = 1
        break
    done = [0] * N
    for i in range(N-1):
        if N-1 > count[i]:
            if done[sc[i][count[i]]-1] == 0 and done[i] == 0:
                if sc[sc[i][count[i]]-1][count[sc[i][count[i]]-1]] == i+1:
                    done[sc[i][count[i]]-1] = 1
                    done[i] = 1
                    count[sc[i][count[i]]-1] += 1
                    count[i] += 1
    if done == [0] * N:
        if count == fin:
            break
        else:
            ans = -1
            break
    ans += 1
if chk == 0:
    print(ans)
else:
    print(N*(N-1)//2)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
import collections
import copy
def input(): return sys.stdin.readline().strip()
N = int(input())
sc = [[int(i) for i in input().split()] for i in range(N)]
count = [0] * N
done = [0] * N
fin = [N-1] * N
ans = 0
for j in range(N*(N-1)//2):
    done = [0] * N
    for i in range(N-1):
        if N-1 > count[i]:
            if done[sc[i][count[i]]-1] == 0 and done[i] == 0:
                if sc[sc[i][count[i]]-1][count[sc[i][count[i]]-1]] == i+1:
                    done[sc[i][count[i]]-1] = 1
                    done[i] = 1
                    count[sc[i][count[i]]-1] += 1
                    count[i] += 1
    if done == [0] * N:
        if count == fin:
            break
        else:
            ans = -1
            break
    ans += 1
print(ans)

Fixed submission:
import sys
import collections
import copy
def input(): return sys.stdin.readline().strip()
N = int(input())
sc = [[int(i) for i in input().split()] for i in range(N)]
count = [0] * N
done = [0] * N
fin = [N-1] * N
ans = 0
chk = 0
for j in range(N*(N-1)//2):
    if j >= 4000:
        chk = 1
        break
    done = [0] * N
    for i in range(N-1):
        if N-1 > count[i]:
            if done[sc[i][count[i]]-1] == 0 and done[i] == 0:
                if sc[sc[i][count[i]]-1][count[sc[i][count[i]]-1]] == i+1:
                    done[sc[i][count[i]]-1] = 1
                    done[i] = 1
                    count[sc[i][count[i]]-1] += 1
                    count[i] += 1
    if done == [0] * N:
        if count == fin:
            break
        else:
            ans = -1
            break
    ans += 1
if chk == 0:
    print(ans)
else:
    print(N*(N-1)//2)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
import collections
import copy
N = int(input())
sc = [[int(i) for i in input().split()] for i in range(N)]
count = [0] * N
done = [0] * N
fin = [N-1] * N
ans = 0
for j in range(N*(N-1)//2):
    done = [0] * N
    for i in range(N-1):
        if N-1 > count[i]:
            if done[sc[i][count[i]]-1] == 0 and done[i] == 0:
                if sc[sc[i][count[i]]-1][count[sc[i][count[i]]-1]] == i+1:
                    done[sc[i][count[i]]-1] = 1
                    done[i] = 1
                    count[sc[i][count[i]]-1] += 1
                    count[i] += 1
    if done == [0] * N:
        if count == fin:
            break
        else:
            ans = -1
            break
    ans += 1
print(ans)

Fixed submission:
import sys
import collections
import copy
def input(): return sys.stdin.readline().strip()
N = int(input())
sc = [[int(i) for i in input().split()] for i in range(N)]
count = [0] * N
done = [0] * N
fin = [N-1] * N
ans = 0
chk = 0
for j in range(N*(N-1)//2):
    if j >= 4000:
        chk = 1
        break
    done = [0] * N
    for i in range(N-1):
        if N-1 > count[i]:
            if done[sc[i][count[i]]-1] == 0 and done[i] == 0:
                if sc[sc[i][count[i]]-1][count[sc[i][count[i]]-1]] == i+1:
                    done[sc[i][count[i]]-1] = 1
                    done[i] = 1
                    count[sc[i][count[i]]-1] += 1
                    count[i] += 1
    if done == [0] * N:
        if count == fin:
            break
        else:
            ans = -1
            break
    ans += 1
if chk == 0:
    print(ans)
else:
    print(N*(N-1)//2)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
import collections
import copy
N = int(input())
sc = [[int(i) for i in input().split()] for i in range(N)]
count = [0] * N
done = [0] * N
fin = [N-1] * N
ans = 0
while count != fin:
    done = [0] * N
    for i in range(N-1):
        if N-1 > count[i]:
            if done[sc[i][count[i]]-1] == 0 and done[i] == 0:
                if sc[sc[i][count[i]]-1][count[sc[i][count[i]]-1]] == i+1:
                    done[sc[i][count[i]]-1] = 1
                    done[i] = 1
                    count[sc[i][count[i]]-1] += 1
                    count[i] += 1
    ans += 1
    if done == [0] * N:
        if count == fin:
            break
        else:
            ans = -1
            break
print(ans)

Fixed submission:
import sys
import collections
import copy
def input(): return sys.stdin.readline().strip()
N = int(input())
sc = [[int(i) for i in input().split()] for i in range(N)]
count = [0] * N
done = [0] * N
fin = [N-1] * N
ans = 0
chk = 0
for j in range(N*(N-1)//2):
    if j >= 4000:
        chk = 1
        break
    done = [0] * N
    for i in range(N-1):
        if N-1 > count[i]:
            if done[sc[i][count[i]]-1] == 0 and done[i] == 0:
                if sc[sc[i][count[i]]-1][count[sc[i][count[i]]-1]] == i+1:
                    done[sc[i][count[i]]-1] = 1
                    done[i] = 1
                    count[sc[i][count[i]]-1] += 1
                    count[i] += 1
    if done == [0] * N:
        if count == fin:
            break
        else:
            ans = -1
            break
    ans += 1
if chk == 0:
    print(ans)
else:
    print(N*(N-1)//2)