#include <bits/stdc++.h>

using namespace std;

const int MaxN=100010;
vector<int> g[MaxN];
int niv[MaxN],size[MaxN],val[MaxN],nr_lanturi;
int lant[MaxN],poz_lant[MaxN],lant_size[MaxN],lant_tata[MaxN];
vector<int> arb[MaxN];

void dfs1(int nod,int tata,int lev)
{
	size[nod]=1;
	niv[nod]=lev;
	for(auto fiu : g[nod])
		if(fiu!=tata)
		{
			dfs1(fiu,nod,lev+1);
			size[nod]+=size[fiu];
		}
}

void dfs2(int nod,int tata,int l)
{
	lant[nod]=l;
	poz_lant[nod]=++lant_size[l];
	int heavy=0;
	for(auto fiu : g[nod])
		if(fiu!=tata && size[fiu]>size[heavy]) heavy=fiu;
	if(!heavy) return;
	dfs2(heavy,nod,l);
	for(auto fiu : g[nod])
		if(fiu!=tata && fiu!=heavy)
		{
			lant_tata[++nr_lanturi]=nod;
			dfs2(fiu,nod,nr_lanturi);
		}
}

void arbint_update(int nod,int st,int dr,int poz,int val,vector<int> &arb)
{
    if(st==dr) arb[nod]=val;
    else
    {
        int mid=(st+dr)/2;
        if(poz<=mid) arbint_update(nod*2,st,mid,poz,val,arb);
        else arbint_update(nod*2+1,mid+1,dr,poz,val,arb);
        arb[nod]=max(arb[nod*2],arb[nod*2+1]);
    }
}

int arbint_query(int nod,int st,int dr,int left,int right,vector<int> &arb)
{
    if(left<=st && dr<=right) return arb[nod];
    else
    {
        int mid=(st+dr)/2,ret=0;
        if(left<=mid) ret=max(ret,arbint_query(nod*2,st,mid,left,right,arb));
        if(mid<right) ret=max(ret,arbint_query(nod*2+1,mid+1,dr,left,right,arb));
        return ret;
    }
}

int main()
{
	freopen("heavypath.in", "r", stdin);
	freopen("heavypath.out", "w", stdout);
	int n,m,x,y,tip;
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++) scanf("%d",&val[i]);
	for(int i=1;i<n;i++)
	{
		scanf("%d%d",&x,&y);
		g[x].push_back(y);
		g[y].push_back(x);
	}
	dfs1(1,0,0);
	nr_lanturi++;
	dfs2(1,0,nr_lanturi);
	for(int i=1;i<=nr_lanturi;i++)
		arb[i].resize(4*lant_size[i]);
	for(int i=1;i<=n;i++)
        arbint_update(1,1,lant_size[lant[i]],poz_lant[i],val[i],arb[lant[i]]);
	for(int i=1;i<=m;i++)
	{
			scanf("%d%d%d",&tip,&x,&y);
			if(tip==0) arbint_update(1,1,lant_size[lant[x]],poz_lant[x],y,arb[lant[x]]);
			else
			{
					int ret=0;
					while(lant[x]!=lant[y])
					{
							if(niv[lant_tata[lant[x]]]<niv[lant_tata[lant[y]]]) swap(x,y);
							ret=max(ret,arbint_query(1,1,lant_size[lant[x]],1,poz_lant[x],arb[lant[x]]));
							x=lant_tata[lant[x]];
					}
					if(poz_lant[x]>poz_lant[y]) swap(x,y);
					ret=max(ret,arbint_query(1,1,lant_size[lant[x]],poz_lant[x],poz_lant[y],arb[lant[x]]));
					printf("%d\n",ret);
			}
	}
	return 0;
}