staticlca

#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cstdlib>

#include <algorithm>
#include <numeric>
#include <limits>
#include <functional>
#include <stack>
#include <vector>
#include <set>
#include <map>
#include <queue>

#define LOG(FMT...) fprintf(stderr, FMT)

using namespace std;

typedef long long ll;
typedef unsigned long long ull;

const int N = 500100;

namespace Tree {
	struct Edge {
		int v;
		Edge* next;
	};

	int n, s;

	Edge* g[N];

	void adde(int u, int v) {
		static Edge pool[N * 2];
		static Edge* p = pool;
		p->v = v;
		p->next = g[u];
		g[u] = p;
		++p;
	}

	namespace StaticLCA {
		const int L = 20;

		int lgn;

		int tour[N];
		int typ[N / L];
		int discst[N / L][L];
		int pre[1 << (L >> 1)][L >> 1][L >> 1];

		void dfs(int u) {

		}

		void build() {
			while ((1 << lgn))
		}

		int lca(int u, int v) {

			return 0;
		}
	}
}

int main() {
#ifdef LBT
	freopen("test.in", "r", stdin);
	int nol_cl = clock();
#endif

	int m;
	scanf("%d%d%d", &Tree::n, &m, &Tree::s);
	for (int rep = 1; rep < Tree::n; ++rep) {
		int u, v;
		scanf("%d%d", &u, &v);
		Tree::adde(u, v);
		Tree::adde(v, u);
	}
	Tree::StaticLCA::build();
	while (m--) {
		int u, v;
		scanf("%d%d", &u, &v);
		printf("%d\n", Tree::StaticLCA::lca(u, v));
	}

#ifdef LBT
	LOG("Time: %dms\n", int((clock() - nol_cl) / (double)CLOCKS_PER_SEC * 1000));
#endif
	return 0;
}