Abandoned warehouse

n, m = [int(x) for x in input().split()]

classroom = [[] for i in range(n + 1)]
for i in range(m):
    a, b = [int(x) for x in input().split()]
    classroom[a].append(b)
    classroom[b].append(a)

team = [0] * (n + 1)
print(*classroom)
def assign2(start):
    for i in classroom[start]:
        if not set(classroom[i]).intersection(classroom[start]):
            team[i] = 2
        else:
            return True
    return False

impossible = False
for i in range(1, n + 1):
    if team[i] == 0:
        team[i] = 1
        impossible = assign2(i)
    if impossible:
        break


if not impossible:
    del team[0]
    print(*team)
else:
    print("IMPOSSIBLE")

Test 1

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...

Test 2

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...

Test 3

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...

Test 4

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...

Test 5

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...

Test 6

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...

Test 7

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...

Test 8

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...

Test 9

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...

Test 10

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...

Test 11

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...

Test 12

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...

Test 13

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...

Test 14

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...

Test 15

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...

Test 16

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 5, in <module>
    a, b =...