#include<bits/stdc++.h>
#define Gc() getchar()
#define Me(x,y) memset(x,y,sizeof(x))
#define Mc(x,y) memcpy(x,y,sizeof(x))
#define d(x,y) ((m)*(x-1)+(y))
#define R(n) (rnd()%(n)+1)
#define Pc(x) putchar(x)
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define eb emplace_back
#define all(x) x.begin(),x.end()
using namespace std;using ll=long long;using db=double;using lb=long db;using ui=unsigned;using ull=unsigned long long;using pii=pair<int,int>;
const int N=2e5+5,M=N*4+5,K=1000+5,mod=1e9+7,Mod=mod-1;const db eps=1e-9;const ll INF=1e18+7;mt19937 rnd(time(0));
#define Tp template<typename T>
#define Ts template<typename T,typename... Ar>
namespace Debug{
	Tp void _debug(char* f,T t){cerr<<f<<'='<<t<<endl;}
	Ts void _debug(char* f,T x,Ar... y){while(*f!=',') cerr<<*f++;cerr<<'='<<x<<",";_debug(f+1,y...);}
	#ifdef LOCAL
	#define gdb(...) _debug((char*)#__VA_ARGS__,__VA_ARGS__)
	#else 
	#define gdb(...) void()
	#endif
}using namespace Debug;
int n,m,q;vector<int> S[N];
int fa[N],d[N],siz[N],son[N],tp[N];
void dfs1(int x,int La){
	fa[x]=La;siz[x]=1;d[x]=d[La]+1;
	for(int i:S[x]) if(i^La) dfs1(i,x),siz[x]+=siz[i],siz[i]>siz[son[x]]&&(son[x]=i);
}
void dfs2(int x,int La){
	tp[x]=La;if(son[x]) dfs2(son[x],La);
	for(int i:S[x]) if(i^fa[x]&&i^son[x]) dfs2(i,i);
}
int LCA(int x,int y){
	while(tp[x]^tp[y]){
		if(d[tp[x]]<d[tp[y]]) swap(x,y);
		x=fa[tp[x]];
	}
	return d[x]<d[y]?x:y;
}
int B[N];
int dist(int x,int y){return d[x]+d[y]-2*d[LCA(x,y)];}
int calc(int x){
	return dist(B[x-1],B[x])+dist(B[x],B[x+1])==dist(B[x-1],B[x+1]);
}
void Solve(){
	int i,j;scanf("%d%d%d",&n,&m,&q);
	for(i=1;i<n;i++){
		int x,y;scanf("%d%d",&x,&y);
		S[x].push_back(y);S[y].push_back(x);
	}
	dfs1(1,0);dfs2(1,1);
	for(i=1;i<=m;i++) scanf("%d",&B[i]);
	int cnt=0;
	for(i=2;i<n;i++) cnt+=calc(i);
	while(q--){
		int x,y;scanf("%d%d",&x,&y);
		for(int i=x-1;i<=x+1;i++) if(1<i&&i<n) cnt-=calc(i);
		B[x]=y;
		for(int i=x-1;i<=x+1;i++) if(1<i&&i<n) cnt+=calc(i);
		printf("%d\n",m-cnt);
	}
}
int main(){
	int t=1;
	// scanf("%d",&t);
	while(t--) Solve();
	cerr<<clock()*1.0/CLOCKS_PER_SEC<<'\n';
}