#include <bits/stdc++.h>

using namespace std;
ifstream r("heavypath.in");
ofstream w("heavypath.out");
int n, i, j, nr, m, np, x, y, op, k, sol, mx, pu, val, a, b, ex, rez;
int ct[100002], v[100002], tt[100002], pth[100002], pos[100002], ext[100002], he[100002], ai[400002], st[100002];
vector<int> ad[100002];
void dfs_cate(int n)
{
	ct[n]=1;
	for(int i:ad[n]){
		if(!ct[i])
		{
			dfs_cate(i);
			ct[n]+=ct[i];
		}
	}
}
void make_paths(int n,int t,int h,int nw)
{
	st[++ex]=n;
	if(nw) {
		np++;
		pos[n]=1;
		pth[n]=np;
		ext[n]=ex-1;
		tt[n]=t;
		he[n]=h-1;
	}
	else {
		pos[n]=pos[t]+1;
		pth[n]=pth[t];
		ext[n]=ext[t];
		he[n]=he[t];
		tt[n]=tt[t];
	}
	if(ad[n].size()==1 && n!=1){
		return;
	}
	int ki=0;
	for(int i:ad[n]){
		if(ct[i]<ct[n] && ct[i]>ct[ki]){
			ki=i;
		}
	}
	make_paths(ki, n, h+1, 0);
	for(int i:ad[n]){
		if(ct[i]<ct[n] && i!=ki){
			make_paths(i, n, h+1, 1);
		}
	}
}
void build(int n,int l,int r)
{
	if(l==r)
	{
		ai[n]=v[st[++k]];
		return;
	}
	int m=(l+r)/2;
	build(2*n,l,m);
	build(2*n+1,m+1,r);
	ai[n]=max(ai[2*n],ai[2*n+1]);
}
void true_query(int n,int l,int r)
{
	if(a<=l && r<=b)
	{
		rez=max(rez, ai[n]);
		return;
	}
	int m=(l+r)/2;
	if(a<=m){
        true_query(2*n,l,m);
	}
	if(b>m){
        true_query(2*n+1,m+1,r);
	}
}
int query(int a,int b)
{
	rez=0;
	::a=a;
	::b=b;
	true_query(1,1,n);
	return rez;
}
void true_update(int n,int l,int r)
{
	if(l==r)
	{
		ai[n]=b;
		return;
	}
	int m=(l+r)/2;
	if(a<=m){
        true_update(2*n,l,m);
	}
	else{
        true_update(2*n+1,m+1,r);
	}
	ai[n]=max(ai[2*n],ai[2*n+1]);
}
void update(int pos,int val)
{
	a=pos;
	b=val;
	true_update(1,1,n);
}
int main() {

	r>>n>>m;
	for(i=1;i<=n;i++){
		r>>v[i];
	}
	for(i=1;i<n;i++)
	{
		r>>x>>y;
		ad[x].push_back(y);
		ad[y].push_back(x);
	}
	dfs_cate(1);
	make_paths(1,0,1,1);
	k=0;
	build(1,1,n);
	while(m--)
	{
		r>>op>>x>>y;
		if(op==0){
			update(ext[x]+pos[x], y);
		}
		else
		{
			sol=0;
			while(1)
			{
				if(pth[x]==pth[y])
				{
					sol=max(sol, query(ext[x]+min(pos[x],pos[y]), ext[x]+max(pos[x],pos[y])));
					break;
				}
				if(he[x]<he[y]){
                        k=x;
                        x=y;
                        y=k;
				}
				sol=max(sol, query(ext[x]+1,ext[x]+pos[x]));
				x=tt[x];
			}
			w<<sol<<"\n";
		}
	}
}