#include <cstring>
#include <iostream>
using namespace std;
int ne[10010];
int main() {
int n ;
int hn;
cin >> n >> hn;
int nc = n;
memset(ne, -1, sizeof(ne));
n--;
while (n) {
int a, b;
cin >> a >> b;
if (ne[b] != -1) {
int sw = ne[b];
ne[b] = a;
ne[a] = sw;
} else {
ne[b] = a;
}
n--;
}
int de;
cin >> de;
while (hn!=-1) {
if (hn == de) {
hn = ne[hn];
continue;
};
cout << hn << ' ';
hn = ne[hn];
}
}
// 64 位输出请用 printf("%lld")

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