read N: n32; // number of nodes

assume 1 <= N <= 1_000;

for u upto N {
    read D[u]: n32; // degree of u

    assume 0 <= D[u] <= N - 1;

    for i upto D[u] {
        read A[u][i]: n32; // adjacency list

        assume 0 <= A[u][i] <= N - 1;
        assume A[u][i] != u; // no self loops
    }
}

call find_cycle(N, D, A) -> L: n32; // length of cycle

write L;

for i upto L {
    call get_cycle_node(i) -> u: n32; // i-th node in the cycle
    write u;
}