#include<bits/stdc++.h>
using namespace std;
const int N=500010;
int n,m,s,father[N],ans[N];
bool vis[N];
vector<int>vec[N];
vector<pair<int,int> >question[N];
int find(int);
void merge(int,int);
void Tarjan(int);
int main()
{
	cin>>n>>m>>s;
	for(int i=1;i<=n;i++)
	{
		father[i]=i; 
	}
	for(int i=1;i<=n-1;i++)
	{
		int x,y;
		cin>>x>>y;
		vec[x].push_back(y);
		vec[y].push_back(x);
	}
	for(int i=1;i<=m;i++)
	{
		int x,y;
		cin>>x>>y;
		if(x==y)
		{
			ans[i]=x;
		}
		else
		{
			question[x].push_back(pair<int,int>(y,i));
            question[y].push_back(pair<int,int>(x,i));
		}
	}
	Tarjan(s);
	for(int i=1;i<=m;i++)
	{
		cout<<ans[i]<<endl;
	}
	return 0;
}
void Tarjan(int x)
{
	vis[x]=true;
	for(int i=0;i<=vec[x].size()-1;i++)
	{
		int t=vec[x][i];
		if(vis[t])
		{
			continue;
		}
		else
		{
			Tarjan(t);
			merge(t,x);
		}
	}
	for(int i=0;i<=question[x].size()-1;i++)
	{
		int t=question[x][i].first;
		int number=question[x][i].second;
		if(vis[t])
		{
			ans[number]=find(t);
		}
	}
}
int find(int x)
{
	if(father[x]!=x)
	{
		father[x]=find(father[x]);
	}
	return father[x];
}
void merge(int x,int y)
{
	int son1=find(x);
	int son2=find(y);
	father[son1]=son2;
}