#include <cmath>

#include <cstdio>

#include <cstring>

#include <iostream>

#include <algorithm>

using namespace std;

#define F(i,j,k) for (int i=j;i<=k;++i)

#define D(i,j,k) for (int i=j;i>=k;--i)

#define maxn 100005

int n,m,col[maxn],h[maxn],to[maxn],ne[maxn],en=0;

int f[maxn][20],dep[maxn],sta[maxn],top=0,blo,cnt;

int bel[maxn],dfsid[maxn],tot=0,hav[maxn],in[maxn];

int nowans,ans[maxn],siz[maxn];

int read()

{

    int x=0,f=1; char ch=getchar();

    while (ch<'0'||ch>'9') {if (ch=='-') f=-1; ch=getchar();}

    while (ch>='0'&&ch<='9') {x=x*10+ch-'0'; ch=getchar();}

    return x*f;

}

void add(int a,int b)

{to[en]=b;ne[en]=h[a];h[a]=en++;}

void dfs(int x,int fa)

{

	dfsid[x]=++tot;f[x][0]=fa;

	if (siz[bel[fa]]==blo) bel[x]=++cnt;

	else bel[x]=bel[fa];

	siz[bel[x]]++;

	for (int i=h[x];i>=0;i=ne[i])

	if (to[i]!=fa){

		dep[to[i]]=dep[x]+1;

		dfs(to[i],x);

	}

}

struct Query{

	int u,v,a,b,id;

	void gett(){

		u=read();v=read();a=read();b=read();

		if (dfsid[u]>dfsid[v]) swap(u,v);

	}

}b[maxn];

bool cmp(Query x,Query y)

{

	return bel[x.u]==bel[y.u]?

	bel[x.v]<bel[y.v]:bel[x.u]<bel[y.u];

}

int lca(int a,int b)

{

	if (dep[a]<dep[b]) swap(a,b);

	if (a==b) return a;

	int dist=dep[a]-dep[b];

	D(i,15,0) if (dist&(1<<i)) a=f[a][i];

	if (a==b) return a;

	D(i,15,0) if (f[b][i]!=f[a][i])

	{

		b=f[b][i];

		a=f[a][i];

	}

	return f[a][0];

}

void rev(int x)

{

	if (!x) return;

	if (in[x])

	{

		in[x]^=1,hav[col[x]]--;

		if (hav[col[x]]==0) nowans--;

	}

	else

	{

		in[x]^=1,hav[col[x]]++;

		if (hav[col[x]]==1) nowans++;

	}

}

void rever(int x,int y)

{

	int z=lca(x,y);

	while (x!=z) rev(x),x=f[x][0];

	while (y!=z) rev(y),y=f[y][0];

}

int main()

{

	memset(h,-1,sizeof h);

	n=read();m=read();

	blo=sqrt(n+1)+1e-5;

	F(i,1,n)

	col[i]=read();

	F(i,1,n)

	{

		int a,b;

		a=read();b=read();

		add(a,b);add(b,a);

	}

	dfs(0,0); while(top)bel[sta[top--]]=cnt;

	F(i,1,15) F(j,0,n) f[j][i]=f[f[j][i-1]][i-1];

	F(i,1,m) b[i].gett(),b[i].id=i;

	sort(b+1,b+m+1,cmp);

	int nowu=0,nowv=0;

	F(i,1,m)

	{

		rever(nowu,b[i].u);

		rever(nowv,b[i].v);

		nowu=b[i].u;nowv=b[i].v;

		rev(lca(b[i].u,b[i].v));

		ans[b[i].id]=nowans-(hav[b[i].a]&&hav[b[i].b]&&(b[i].a!=b[i].b));

		rev(lca(b[i].u,b[i].v));

	}

	F(i,1,m) printf("%d\n",ans[i]);

}