n, m = map(int, input().split())
assert(2 <= n <= 500)
assert(m == n * (n - 1) // 2)
edges = set()
for i in range(m):
    u, v, w = map(int, input().split())
    assert(1 <= u <= n)
    assert(1 <= v <= n)
    assert(u != v)
    assert(w == 1)
    edges.add((min(u, v), max(u, v)))
f = True
try:
    input()
    f = False
except:
    pass
assert(f)
assert(len(edges) == m)