include <bits/stdc++.h>

using namespace std; vector a[1005]; bool vv[1005]; int n, m, s; int cnt;

void dfs(int u) {

vv[u] = true;
cnt++;
cout << u << " ";
for (int v : a[u]) {
	if (!vv[v]) {
		dfs(v);
		cout << u << " ";
	}
}

}

int main() {

int t;
cin >> t;
while (t--) {
	cin >> n >> m >> s;
	for (int i = 1; i <= n; ++i) {
		a[i].clear();
		vv[i] = false;
	}
	cnt = 0;
	for (int i = 0; i < m; ++i) {
		int u, v;
		cin >> u >> v;
		a[u].push_back(v);
		a[v].push_back(u);
	}

	for (int i = 1; i <= n; ++i) {
		sort(a[i].begin(), a[i].end());
	}
	dfs(s);
	if (cnt < n) {
		cout << "0";
	}
	cout << endl;
}

return 0;

}