4 4
1 2
1 3
2 4
3 4

1 2 3 4

from collections import deque
n, m = map(int, input().split())
graph = [[] for _ in range(n+1)]
indeg = [0]*(n+1)
for _ in range(m):
    a, b = map(int, input().split())
    graph[a].append(b)
    indeg[b] += 1
q = deque(sorted([i for i in range(1, n+1) if indeg[i] == 0]))
result = []
while q:
    node = q.popleft()
    result.append(node)
    candidates = []
    for nxt in graph[node]:
        indeg[nxt] -= 1
        if indeg[nxt] == 0:
            candidates.append(nxt)
    for c in sorted(candidates):
        q.append(c)
if len(result) == n:
    print(*result)
else:
    print('CYCLE')