include

include

using namespace std; vectormap[500001];

struct query {

int index;
int other;

}; int ans[500001]; int group[500001]; vectorq[500001];

int find(int x) {

if (x != group[x]) {
	group[x] = find(group[x]);
}
return group[x];

}

bool vis[5000011];

void dfs(int node, int father) {

vis[node] = true;
for (int i = 0; i < q[node].size(); i++)
	if (vis[q[node][i].other]) {
		ans[q[node][i].index ] = find(q[node][i].other );
	}
for (int i = 0; i < map[node].size(); i++)
	if (map[node][i] != father) {
		dfs(map[node][i], node);
	}
group[node] = father;

}

int main() {

int n, m, s;
scanf("%d%d%d", & n, &m, &s);
for (int i = 1; i <= n; i++)
	group[i] = i;
for (int i = 0; i < n - 1; i++) {
	int x, y;
	scanf("%d%d", & x, &y);
	map[x].push_back(y);
	map[y].push_back(x);
}
for (int i = 0; i < m; i++) {
	int a, b;
	scanf("%d%d", & a, &b);
	q[a].push_back({i, b});
	q[b].push_back({i, a});
}
dfs(s, 0);
for (int i = 0; i < m; i++)
	printf("%d\n", ans[i]);
return 0;

}