#include <bits/stdc++.h>
using namespace std;
int n, S, T;
vector<int> g[50005];
namespace makedis {
int d[50005], p[50005][20];
int LCA(int x, int y) {
	if (d[x] < d[y]) swap(x, y);
	for (int i = 17; i >= 0; i--)
		if (d[x] - (1 << i) >= d[y]) x = p[x][i];
	if (x == y) return x;
	for (int i = 17; i >= 0; i--)
		if (p[x][i] ^ p[y][i]) x = p[x][i], y = p[y][i];
	return p[x][0];
}
int dis(int x, int y) { return d[x] + d[y] - 2 * d[LCA(x, y)]; }
void dfs(int x, int fa) {
	p[x][0] = fa, d[x] = d[fa] + 1;
	for (int i = 1; i <= 17; i++) p[x][i] = p[p[x][i - 1]][i - 1];
	for (int y : g[x])
		if (y ^ fa) dfs(y, x);
}
void main() { dfs(1, 0); }
void clear() {
	for (int i = 1; i <= n; i++) d[i] = 0, memset(p[i], 0, sizeof(p[i]));
}
} // namespace makedis
int st[50005], top, onl[50005], pa[50005], num, tans[50005], tu;
int ans[50005], m, bel[50005], len[50005];
int ok1, A1, B1; // 情况1：有dep>=3的子树
int ok2, A2, B2; // 情况2：有dep>=2的子树且不止一个
int ok3, A3, B3; // 情况3：有dep>=2的点且不是T,T-1
void dfs1(int x, int fa) {
	st[++top] = x;
	if (x == T) {
		num = top;
		for (int i = 1; i <= top; i++) pa[i] = st[i], onl[st[i]] = 1;
	}
	for (int y : g[x]) {
		if (y == fa) continue;
		dfs1(y, x);
	}
	top--;
}
void clear() {
	makedis::clear();
	for (int i = 1; i <= n; i++) {
		st[i] = onl[i] = pa[i] = ans[i] = tans[i] = 0;
		bel[i] = len[i] = 0, g[i].clear();
	}
	top = num = tu = m = 0;
	ok1 = A1 = B1 = 0;
	ok2 = A2 = B2 = 0;
	ok3 = A3 = B3 = 0;
}
void dfs2(int x, int fa) {
	tans[++tu] = x; // 让tans加上x子树，最终以x儿子/x结尾
	sort(g[x].begin(), g[x].end(), [](int x, int y) { return len[x] > len[y]; });
	int fir = 0, sec = 0;
	for (int y : g[x]) {
		if (y == fa || onl[y]) continue;
		sort(g[y].begin(), g[y].end(), [](int x, int y) { return len[x] < len[y]; });
		if (!fir) fir = y;
		else if (!sec) sec = y;
		int O = !ok1, tmp = 0;
		for (int z : g[y]) {
			if (z == x || onl[z]) continue;
			dfs2(z, y);
			int lst = tans[tu];
			if (O && !tmp) tmp = z;
			if (lst != z && O) {
				ok1 = 1, B1 = lst;
			}
		}
		if (O && ok1) A1 = tmp;
		tans[++tu] = y;
	}
	if (sec && len[fir] >= 1 && !ok2) {
		ok2 = 1;
		int i = tu;
		while (tans[i] != x) i--;
		i++;
		A2 = tans[i];
		while (tans[i] != sec) i++;
		B2 = tans[i - 1];
	}
}
void getsz(int x, int fa) {
	len[x] = 0;
	if (!fa) bel[x] = x;
	else bel[x] = bel[fa];
	for (int y : g[x]) {
		if (y == fa || onl[y]) continue;
		getsz(y, x), len[x] = max(len[x], len[y] + 1);
	}
}
bool Try(int x, int y) {
	if (!x) return 0;
	int p1 = 0, p2 = 0;
	for (int i = 1; i <= m; i++) {
		if (ans[i] == x) p1 = i;
		if (ans[i] == y) p2 = i;
	}
	if (p1 > p2) swap(p1, p2);
	reverse(ans + p1, ans + p2 + 1);
	for (int i = 1; i <= m; i++) cout << ans[i] << ' ';
	cout << '\n';
	return 1;
}
void Solve() {
	scanf("%d%d%d", &n, &S, &T);
	for (int i = 1, x, y; i < n; i++) {
		scanf("%d%d", &x, &y);
		g[x].push_back(y), g[y].push_back(x);
	}
	makedis::main();
	dfs1(S, 0);
	for (int i = 1; i <= num; i++) getsz(pa[i], 0);
	for (int i = 1; i <= num; i++) {
		tu = 0, dfs2(pa[i], 0);
		if (len[pa[i]] >= 2 &&
		    (i < num - 1 || (i == num - 1 && len[T] == 0) || (i == num && len[pa[i - 1]] == 0)) &&
		    !ok3) {
			ok3 = 1, A3 = tans[2], B3 = tans[tu];
		}
		if (i < num) {
			for (int j = 1; j <= tu; j++) ans[++m] = tans[j];
		} else {
			for (int j = tu; j >= 1; j--) ans[++m] = tans[j];
		}
	}
	int xsum = 0;
	// for (int i = 1; i <= m; i++) cout << ans[i] << ' ';
	// puts("");
	for (int i = 2; i <= m; i++) {
		xsum ^= makedis::dis(ans[i], ans[i - 1]);
	}
	assert(xsum <= 3);
	if (xsum > 1) {
		if (Try(A1, B1)) return clear();
		if (Try(A2, B2)) return clear();
		if (Try(A3, B3)) return clear();
		if (max(len[pa[num - 1]], len[T]) == 2) {
			int pos1 = m;
			while (ans[pos1] != pa[num - 1]) pos1--;
			if (min(len[pa[num - 1]], len[T]) == 1) {
				Try(ans[pos1 + 1], ans[m - 1]);
				return clear();
			}
			for (int i = 1; i <= pos1; i++) cout << ans[i] << ' ';
			for (int i = 1; i <= m; i++)
				if (makedis::dis(ans[i], pa[num - 1]) == 2 && bel[ans[i]] == pa[num - 1])
					cout << ans[i] << ' ';
			for (int i = 1; i <= m; i++)
				if (makedis::dis(ans[i], T) == 2 && bel[ans[i]] == T) cout << ans[i] << ' ';
			for (int i = 1; i <= m; i++)
				if (makedis::dis(ans[i], pa[num - 1]) == 1 && bel[ans[i]] == pa[num - 1])
					cout << ans[i] << ' ';
			for (int i = 1; i <= m; i++)
				if (makedis::dis(ans[i], T) == 1 && bel[ans[i]] == T) cout << ans[i] << ' ';
			cout << T;
			cout << '\n';
			return clear();
		}
	}
	// 现在就是性质2
	if (xsum > 1) {
		if (min(len[pa[num - 1]], len[T]) == 1 &&
		    max(g[T].size() - 1, g[pa[num - 1]].size() - 1 - (num > 2)) > 1) {
			int i = n;
			while (ans[i] != pa[num - 1]) i--;
			if (g[pa[num - 1]].size() - (num > 2) > g[T].size()) Try(ans[i + 2], ans[n - 1]);
			else Try(ans[i + 1], ans[n - 2]);
			return clear();
		}
		if (num == 3 && len[S] == 1 && len[T] == 1 && len[pa[2]] == 0) {
			if (g[S].size() > 2) {
				cout << S << ' ' << pa[2] << ' ' << ans[2] << ' ';
				for (int i = 1; i < n; i++)
					if (bel[ans[i]] == T) cout << ans[i] << ' ';
				for (int i = 3; i <= n; i++)
					if (bel[ans[i]] == S) cout << ans[i] << ' ';
				cout << T << '\n';
				return clear();
			}
			if (g[T].size() > 2) {
				cout << S << ' ' << ans[n - 1] << ' ';
				for (int i = 2; i < n; i++)
					if (bel[ans[i]] == S) cout << ans[i] << ' ';
				for (int i = 2; i < n - 1; i++)
					if (bel[ans[i]] == T) cout << ans[i] << ' ';
				cout << pa[2] << ' ' << T << '\n';
				return clear();
			}
		}
		if (num >= 4 && len[pa[num - 3]] == 0 && len[pa[num - 2]] == 1 && len[pa[num - 1]] == 0 &&
		    len[T] == 1) {
			return Try(pa[num - 2], pa[num - 1]), clear();
		}
		for (int i = 2; i < m && (i + 1 < m || i == 2); i++) {
			int l = i, r = min(i + 2, m - 1), c[10] = {0};
			for (int j = l; j <= r; j++) c[j - l + 1] = ans[j];
			int xs = xsum;
			for (int j = l; j <= r + 1; j++) xs ^= makedis::dis(ans[j], ans[j - 1]);
			sort(c + 1, c + r - l + 2);
			do {
				int xxs = xs;
				for (int j = l; j <= r + 1; j++) {
					int A = ans[j], B = ans[j - 1];
					if (l <= j && j <= r) A = c[j - l + 1];
					if (l <= j - 1 && j - 1 <= r) B = c[j - l];
					xxs ^= makedis::dis(A, B);
				}
				if (xxs < 2) {
					for (int j = l; j <= r; j++) ans[j] = c[j - l + 1];
					for (int i = 1; i <= m; i++) cout << ans[i] << ' ';
					cout << '\n';
					return clear();
				}
			} while (next_permutation(c + 1, c + r - l + 2));
		}
	}
	// xsum = 0;
	// for (int i = 2; i <= m; i++) xsum ^= (makedis::dis(ans[i], ans[i - 1]));
	//  cout << xsum << '\n';
	for (int i = 1; i <= m; i++) cout << ans[i] << ' ';
	cout << '\n';
	clear();
}
int main() {
	int t;
	scanf("%d", &t);
	while (t--) Solve();
}