import java.util.*;

public class Main {
	public static void main (String[] args) {
    	Scanner sc = new Scanner(System.in);
    	int n = sc.nextInt();
    	ArrayDeque<ArrayDeque<Integer>> all = new ArrayDeque<>();
    	for (int i = 0; i < n; i++) {
    	    int p = sc.nextInt();
    	    if (p == 0) {
    	        continue;
    	    }
    	    ArrayDeque<Integer> tmp = new ArrayDeque<>();
    	    for (int j = 0; j < p; j++) {
    	        tmp.add(sc.nextInt());
    	    }
    	    all.add(tmp);
    	}
    	StringBuilder sb = new StringBuilder();
    	while (all.size() > 0) {
    	    ArrayDeque<Integer> tmp = all.poll();
    	    if (sb.length() > 0) {
    	        sb.append(" ");
    	    }
    	    sb.append(tmp.poll());
    	    if (tmp.size() > 0) {
    	        all.add(tmp);
    	    }
    	}
    	System.out.println(sb);
    }
}