Building Teams

buffer = input().split(" ")
n = int(buffer[0])
m = int(buffer[1])
color = [0 for _ in range(n)]
graph = [[] for _ in range(n)]
for _ in range(m):
    buffer = input().split(" ")
    a = int(buffer[0])
    b = int(buffer[1])
    graph[a-1].append(b-1)
    #graph[b-1].append(a-1)

def color_neighbors(i):
    for j in graph[i]:
        if color[j] == color[i]:
            print("IMPOSSIBLE")
            #print(i,j,color,graph)
            exit(0)
        elif color[j] == 0:
            color[j] = 3 - color[i]
            color_neighbors(j)

for i in range(n):
    if color[i] == 0:
        color[i] = 1
    color_neighbors(i)

for c in color:
    assert 1<=c<=2

print(" ".join(list(map(str,color))))

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED