#include <bits/stdc++.h>
using namespace std;int main() {
int n;
cin >> n;
vector<int> a[n+1];
for (int i = 0; i < n; i++) {
int x,y;
cin >> x >> y;
for (int j = 0; j < a[y].size(); j++) {
a[x].push_back(a[y][j]);
}
a[x].clear(); vector<int>().swap(a[x]);
}
for (int i = 0; i < n; i++) {
if (a[i].size() == 0) {
cout << endl;
continue;
}
for (int j = 0; j < a[i].size(); j++) {
cout << a[i][j] << " ";
}
cout << endl;
}
return 0;
}