# UUID: 8e2e1404-cc24-4b01-ba83-baca373c1452
n,k=map(int,input().split())
l=[[] for _ in range(n+1)]
be=[0]*(n+1)
for i in range(k):
    x=list(map(int,input().split()))
    l[x[0]].append(x[1])
    be[x[1]]+=1
#print(l)
munka=[]
volt=set()
volt2=set()
m=0
mode=1
swap=-1
for i in range(1,n+1):
    if be[i]==0:
        munka.append(i)
        volt.add(i)
for _ in range(n):
    #print(munka,be)
    if len(munka)<=m:
        mode=0
        break
    x=munka[m]
    #print(x)
    volt2.add(x)
    m+=1
    for i in l[x]:
        #print(i,volt2)
        if i not in volt:
            be[i]-=1
            if be[i]==0:
                munka.append(i)
                volt.add(i)

if mode==1:
    for i in range(n-1):
        if munka[i+1] not in l[munka[i]]:
            mode=2
            swap=i
            break

print(mode)
for i in range(mode):
    for j in range(len(munka)):
        if i==1 and  j==swap:
            print(munka[j+1],end=" ")
        elif i==1 and j==swap+1:
            print(munka[j-1],end=" ")
        else:
            print(munka[j],end=" ")
    print()