#include <bits/stdc++.h>
#define F first
#define S second
#define pb push_back
#define ppb pop_back
#define ep insert
#define endl '\n'
#define elif else if
#define pow pwr
#define sqrt sqrtt
#define int long long
#define ll long long
typedef unsigned long long ull;
using namespace std;
const int N=305;
int n,par[N][N],b[N],m,q,euler[N][2*N],c,dis[N][N],f[N][N],lg[2*N];
vector<int> adj[N];
bool vis[N];
pair<int,int> st[N][20][2*N];
void dfs(int x,int p,int r){
par[r][x]=p;
euler[r][++c]=x;
f[r][x]=c;
dis[r][x]=dis[r][p]+1;
for (auto u:adj[x]){
if (u==p) continue;
dfs(u,x,r);
euler[r][++c]=x;
}
return;
}
void build(){
for (int r=1;r<=n;r++){
for (int i=1;i<=c;i++) st[r][0][i]={dis[r][euler[r][i]],euler[r][i]};
for (int i=1;i<20;i++){
for (int j=1;j+(1<<i)<=c+1;j++){
st[r][i][j]=min(st[r][i-1][j],st[r][i-1][j+(1<<(i-1))]);
}
}}return;
}
int query(int l,int r,int x){
if (l>r) swap(l,r);
int i=lg[r-l+1];
return min(st[x][i][l],st[x][i][r-(1<<i)+1]).S;
}
int32_t main(){
ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
for (int i=2;i<2*N;i++) lg[i]=lg[i/2]+1;
cin>>n>>m>>q;
for (int i=1;i<n;i++){
int x,y;
cin>>x>>y;
adj[x].pb(y);
adj[y].pb(x);
}
for (int i=1;i<=n;i++) c=0,dfs(i,0,i);
build();
for (int i=1;i<=m;i++) cin>>b[i];
while (q--){
int l,r;
cin>>l>>r;
int ans=INT_MAX;
for (int s=2;s<=2;s++){
int lca=b[l];
for (int i=l;i<=r;i++){
lca=query(f[s][lca],f[s][b[i]],s);
}
for (int i=l;i<=r;i++){
int x=b[i];
while (dis[s][x]>=dis[s][lca] && !vis[x]){
vis[x]=1;
x=par[s][x];
}
}
int ansx=0;
for (int i=1;i<=n;i++) ansx+=vis[i],vis[i]=0;
ans=min(ansx,ans);
//cout<<ansx<<' ';
}cout<<ans<<endl;
}
return 0;
}
