import sys
readline = sys.stdin.readline

N, M = map(int, readline().split())
assert 2 <= N <= 1000
assert 1 <= M <= min(N*(N-1)//2, 2500)
for _ in range(M):
    u, v, w = map(int, readline().split())
    assert 1 <= u <= N
    assert 1 <= v <= N
    assert 1 <= w <= 10**9

print('ok')