Connected components

n, m = map(int, input().split())

edges = []
while m:
    edges.append(list(map(int, input().split())))
    m -= 1

g = dict()

for v in range(1, n + 1):
    g[v] = []

for a, b in edges:
    g[a].append(b)
    g[b].append(a)

count = 0
visited = set()
res = []

for v in g:
    if v not in visited:
        comp = []
        count += 1
        st = [v]
        visited.add(v)
        while st:
            cur = st.pop()
            comp.append(str(cur))
            for nb in g[cur]:
                if nb not in visited:
                    st.append(nb)
                    visited.add(nb)
        res.append(comp)
print(count)
for comp in res:
    print(len(comp))
    print(' '.join(comp))