#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N=200005;
int n,m,k,s,t,Q,f[N][21],de[N],d[N];
queue<int> q;
vector<int> e[N];
void dfs(int u){
	for (int v:e[u]){
		if (v!=f[u][0]){
			f[v][0]=u;
			de[v]=de[u]+1;
			dfs(v);
		}
	}
}
int lca(int u,int v){
	if (de[u]<de[v]) swap(u,v);
	for (int k=de[u]-de[v],o=0;k;k>>=1,++o)
		if (k&1) u=f[u][o];
	if (u==v) return u;
	for (int j=20;j>=0;--j)
		if (f[u][j]!=f[v][j])
			u=f[u][j],v=f[v][j];
	return f[u][0];
}
int main(){
	freopen("in.txt","r",stdin);
	cin>>n>>k>>Q;
	for (int i=1;i<n;++i){
		cin>>s>>t;
		e[s].push_back(t);
		e[t].push_back(s);
	}
	dfs(1);
	for (int j=1;j<=20;++j)
		for (int i=1;i<=n;++i)
			f[i][j]=f[f[i][j-1]][j-1];
	memset(d,0x3f,sizeof(d));
	for (int i=1;i<=k;++i) 
		cin>>s,d[s]=0,q.push(s);
	while (!q.empty()){
		int u=q.front();
		q.pop();
		for (int v:e[u]){
			if (d[v]>d[u]+1){
				d[v]=d[u]+1;
				q.push(v);
			}
		}
	}
	int u,v;
	while (Q--){
		cin>>u>>v;
		int p=lca(u,v);
		cout<<min(de[u]+de[v]-2*de[p],d[u]+d[v])<<"\n";
	}
}