Building Teams

pupils, friendships = [int(x) for x in input().split()]
adj = [[]for _ in range(pupils+1)]
teams= [1 for _ in range(pupils+1)]

def isConnected(pupil1, pupil2):
    if pupil2 in adj[pupil1] or pupil1 in adj[pupil2]:
        return True
    else:
        return False

def addAdj(adjList, pupil1, pupil2):
    adjList[pupil1].append(pupil2)
    adjList[pupil1].append(pupil2)

def main():
    for i in range(friendships):
        pupil1, pupil2 = [int(x) for x in input().split()]
        addAdj(adj, pupil1, pupil2)
    teams[0] = 0
    for pupil in range(2,pupils+1):
        #change = 0
        #print(pupil)
        for team_members in range(len(teams)):
            if isConnected(pupil, team_members):
                #print(pupil, " is connected to ", team_members)
                if teams[team_members] == 1:
                    teams[pupil] = 2
                else:
                    teams[pupil] = 1
                #change += 1
                break
            else:
                if teams[team_members] == 1:
                    teams[pupil] = 1
                else:
                    teams[pupil] = 2
        #if change >= 2:
        #    print("IMPOSSIBLE")
        #    exit()

    if pupils == friendships:
        print("IMPOSSIBLE")
    else:
        print(*teams[1:])

if __name__ == "__main__":
    main()

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: TIME LIMIT EXCEEDED

Test 7

Verdict: TIME LIMIT EXCEEDED

Test 8

Verdict: TIME LIMIT EXCEEDED

Test 9

Verdict: TIME LIMIT EXCEEDED

Test 10

Verdict: TIME LIMIT EXCEEDED

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: WRONG ANSWER