#include "Annalib.h"
#include <bits/stdc++.h>
using namespace std;

static const int N = 1e5 + 5;
static int n, t, flag[N];
static vector<int> e[N];

static void dfs(int u, int fa) {
	Flag(u, flag[u]);
	for (int v : e[u]) {
		if (v == fa) {
			continue;
		}
		flag[v] = flag[u] ^ (v < u);
		dfs(v, u);
	}
}

void Anna(int K, int N, int T, int A[], int B[]) {
	n = N, t = T;
	for (int i = 0; i < n - 1; i++) {
		int u = A[i], v = B[i];
		e[u].emplace_back(v);
		e[v].emplace_back(u);
	}
	dfs(t, 0);
}

#include "Brunolib.h"
#include <bits/stdc++.h>
using namespace std;

void Bruno(int K, int S, int F, int L, int P[], int Q[]) {
	for (int i = 0; i < L; i++) {
		if ((F ^ Q[i]) == (P[i] > S)) {
			cout << P[i] << endl;
			Answer(P[i]);
			return;
		}
	}
	Answer(S);
}