#include <bits/stdc++.h>
#define N 1000011
#define M N*23
using namespace std;
int n,m;
vector<int> G[N];
int ch[M][2],cnt[M],rt[N],gb[M],a[N];
struct BIT
{
	int c[N];
	int query(int x){int ans=0;for(;x;x-=x&-x)ans^=c[x];return ans;}
	void add(int x,int p){for(;x<=n;x+=x&-x)c[x]^=p;}
	void add(int l,int r,int p){if(l>r)return;add(l,p);add(r+1,-p);}
}Bt,Bx;
void ins(int v,int x)
{
	for(int i=19;~i;--i)
	{
		++cnt[x];
		if(!ch[x][v>>i&1])
		{
			int nw=gb[gb[0]--];ch[nw][0]=ch[nw][1]=cnt[nw]=0;
			ch[x][v>>i&1]=nw;
		}
		x=ch[x][v>>i&1];
	}
	++cnt[x];
}
void del(int v,int x)
{
	for(int i=19;~i;--i)
	{
		if(!--cnt[x])gb[++gb[0]]=x;
		x=ch[x][v>>i&1];
	}
	if(!--cnt[x])gb[++gb[0]]=x;
}
int search(int x,int tag,int v)
{
	int ans=0;
	for(int i=19;~i;--i)
	{
		if(v>>i&1)ans+=cnt[ch[x][((v^tag)>>i&1)^1]];
		x=ch[x][(v^tag)>>i&1];
	}
	ans+=cnt[x];
	return ans;
}
int S,T,C,Cu,Cv,D,dep[N],fa[N],dfn[N],siz[N],rk[N],clk;
void dfsd(int u,int F)
{
	dep[u]=dep[F]+1;fa[u]=F;
	for(int v:G[u])if(v^F)dfsd(v,u);
}
int h[N],fah[N],X[N];
void dfs(int u,int F,int H)
{
	fa[u]=F;
	dfn[u]=++clk;rk[clk]=u;siz[u]=1;fah[u]=H;
	for(int v:G[u])if(v^F)dfs(v,u,H+1),siz[u]+=siz[v],h[u]=max(h[u],h[v]+1);
}
void addnode(int u)
{
	Bt.add(dfn[u],dfn[u]+siz[u]-1,fah[u]);
	Bt.add(1,dfn[u]-1,h[u]);Bt.add(dfn[u]+siz[u],n,h[u]);
	if(fa[u]&&u!=Cu&&u!=Cv)
	{
		del(X[u],rt[fa[u]]);
		X[u]^=h[u]^max(h[u],fah[u]);
		ins(X[u],rt[fa[u]]);
	}
	Bx.add(dfn[u]+1,dfn[u]+siz[u]-1,fah[u]);
	Bx.add(1,dfn[u]-1,h[u]);Bx.add(dfn[u]+siz[u],n,h[u]);
	Bx.add(dfn[u],dfn[u],max(h[u],fah[u]));
}
bool check(int y){return Bx.query(dfn[y])<=max(h[y],fah[y]);}
int main()
{
	scanf("%*d%d%d",&n,&m);
	for(int i=1;i<n;++i){int u,v;scanf("%d%d",&u,&v);G[u].push_back(v);G[v].push_back(u);}
	for(int i=1;i<=n;++i)scanf("%d",a+i);
	dfsd(1,0);
	for(int i=1;i<=n;++i)if(dep[i]>dep[S])S=i;
	dfsd(S,0);
	for(int i=1;i<=n;++i)if(dep[i]>dep[T])T=i;
	D=dep[T]-1;
	C=T;
	for(int _=0;_<D/2;++_)C=fa[C];
	for(int i=M-1;i;--i)gb[++gb[0]]=i;
	if(D&1)
	{
		Cu=C,Cv=fa[C];
		dfs(Cu,Cv,(D+1)/2);
		dfs(Cv,Cu,(D+1)/2);
	}
	else
	{
		dfs(C,0,D/2);
	}
	for(int i=1;i<=n;++i)if(a[i])addnode(i);
	while(m--)
	{
		int x,y;
		scanf("%d%d",&x,&y);
		addnode(x);
		int ans=0;
		for(int z:G[y])ans+=check(z);
		ans+=check(y);
		printf("%d\n",ans);
	}
	fclose(stdin);fclose(stdout);return 0;
}