#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;

const int N = 10010;
int n;
int h[N], e[N], ne[N], idx;
int son[N];
bool st[N];

void add(int a, int b){
    e[idx] = b, ne[idx] = h[a], h[a] = idx ++ ;
}

int dfs(int u){ //树形DP
    int res = 0; //记录最长分枝的结点数目
    son[u] = -1; //记录路径
    for (int i = h[u]; ~i; i = ne[i]){
        int j = e[i];
        int d = dfs(j);
        if (res < d) res = d, son[u] = j;
        else if (res == d) son[u] = min(son[u], j);
    }
    return res + 1;
}

int main(){
    scanf("%d", &n);

    memset(h, -1, sizeof h);
    for (int i = 0; i < n; i ++ ){
        int cnt;
        scanf("%d", &cnt);
        while (cnt -- ){
            int x;
            scanf("%d", &x);
            add(i, x);
            st[x] = true; //标记
        }
    }

    int root = 0;
    while (st[root]) root ++ ;

    printf("%d\n", dfs(root)); 
    printf("%d", root);
    while (son[root] != -1){
        root = son[root];
        printf(" %d", root);
    }

    return 0;
}