def dfs_time(v):
    return
#    global current_time
#    used[v] = True
#    for new_v in L[v]:
#        if not used[new_v]:
#            dfs_time(new_v)
#    order[N - current_time - 1] = v
#    current_time += 1

def dfs_ctc(v):
    return
#    used[v] = True
#    partial.append(v)
#    for new_v in RL[v]:
#        if not used[new_v]:
#            dfs_ctc(new_v)

fin = open('ctc.in', 'r')
line = fin.readline()
N, M = line.split()
N = int(N)
M = int(M)

#L = [[] for _ in xrange(N)]
#RL = [[] for _ in xrange(N)]
#
#for i in xrange(M):
#    line = fin.readline()
#    u, v = line.split(' ')
#    u = int(u) - 1
#    v = int(v) - 1
#    L[u].append(v)
#    RL[v].append(u)
#
#fin.close()

#used = [False] * N
#current_time = 0
#order = [0] * N
#for i in xrange(N):
#    if not used[i]:
#        dfs_time(i)
#
#result = []
#used = [False] * N
#for i in xrange(N):
#    if not used[order[i]]:
#        partial = []
#        dfs_ctc(order[i])
#        result.append(partial)
#
#fout = open('ctc.out', 'w')
#fout.write(str(len(result)) + '\n')
#for l in result:
#    for v in l:
#        fout.write(str(v + 1) + ' ')
#    fout.write('\n')
#fout.close()