n,m = map(int,input().split())
print("YES")
print(2*m)
for i in range(m):
    a,b = map(int,input().split())
    x = list(i for i in range(1,n+1) if i not in [a,b])
    print(* ([a,b] + x))
    print(*(x[::-1] + [a,b]))