#include <iostream>

#define MAXN 100

using namespace std;

int main() {
    // front[a] is the branch just below branch a, or -1 if a is a root
    int front[MAXN+1];
    int cat;
    cin >> cat;

    int branch;

    /* initialize all branches to point to the ground
       so the branches that don't appear on the right side
       of some input are roots */
    for (int i = 1; i <= MAXN; ++i) {
        front[i] = -1;
    }

    // read in the tree description
    while ((cin >> branch) && branch != -1) {
        // peek ahead, if we see a newline then the line is done
        while (cin.peek() != '\n') {
            int higher;
            cin >> higher;
            // the branch "higher" lies directly above "branch"
            front[higher] = branch;
        }
    }

    cout << cat;
    while (front[cat] != -1) {
        // hop down to the next branch
        cat = front[cat];
        cout << ' ' << cat;
    }
    cout << endl;

    return 0;
}