#include<fstream>
#include<vector>
#include<algorithm>

#define NMAX 100005
#define VEC G[nod][i]
#define son (nod<<1)
#define middle ((left+right)>>1)

using namespace std;

ifstream fin("heavypath.in");
ofstream fout("heavypath.out");

vector<int> G[NMAX];
int level[NMAX],TT[NMAX],TT_lant[NMAX],lant[NMAX],under[NMAX];
int AINT[(1<<18)],Maxx,K,L,R,poz,val,what[NMAX];
int n,Q,v[NMAX],k;

void read()
{
	fin>>n>>Q;
	for(int i=1;i<=n;i++)
		fin>>v[i];
	for(int i=1,x,y;i<n;i++)
	{
		fin>>x>>y;
		G[x].push_back(y);
		G[y].push_back(x);
	}
}

void DFS(int nod,int tt)
{
	
	TT[nod]=tt;
	level[nod]=level[tt]+1;
	if(G[nod].size()==1 && nod!=1)
	{
		lant[nod]=++k;
		return;
	}
	int maxim=-1;
	for(size_t i=0;i<G[nod].size();i++)
		if(VEC!=tt)
		{
			DFS(VEC,nod);
			under[nod]+=under[VEC]+1;
			if(maxim<under[VEC])
			{
				maxim=under[VEC];
				lant[nod]=lant[VEC];
			}
		}
}

void update(int left,int right,int nod)
{
	if(left==right)
	{
		AINT[nod]=val;
		return;
	}
	if(poz<=middle)
		update(left,middle,son);
	else
		update(middle+1,right,son+1);
	AINT[nod]=max(AINT[son],AINT[son+1]);   
}

void query(int left,int right,int nod)
{
	if(left>R || right<L)
		return;
	if(L<=left && right<=R)
	{
		Maxx=max(Maxx,AINT[nod]);
		return;
	}
	query(left,middle,son);
	query(middle+1,right,son+1);
}

bool cmp(const int a,const int b)
{
	if(lant[a]==lant[b])
		return level[a]<level[b];
	return lant[a]<lant[b];
}

void group_init()
{
	int nods[NMAX];
	for(int i=1;i<=n;i++)
		nods[i]=i;
	sort(nods+1,nods+n+1,cmp);
	
	for(int i=1,ant=0;i<=n;i++)
	{
		if(lant[nods[i]]!=ant)
		{
			ant=lant[nods[i]];
			TT_lant[ant]=nods[i];
		}
		what[nods[i]]=i;
		poz=i;
		val=v[nods[i]];
		update(1,n,1);
	}
}

int LCA(int x,int y)
{
	while(lant[x]!=lant[y])
	{
		if(level[TT_lant[lant[x]]]>level[TT_lant[lant[y]]])
		{
			x=TT[TT_lant[lant[x]]];
			continue;
		}
		if(level[TT_lant[lant[x]]]<level[TT_lant[lant[y]]])
		{
			y=TT[TT_lant[lant[y]]];
			continue;
		}
		x=TT[TT_lant[lant[x]]];
		y=TT[TT_lant[lant[y]]];
	}
	if(level[x]>level[y])
		return y;
	else
		return x;
}

void Val(int x,int lca,int &sol)
{
	while(level[x]>level[lca])
	{
		Maxx=0;
		R=what[x];
		if(lant[x]==lant[lca])
			L=what[lca];
		else
			L=what[TT_lant[lant[x]]];
		query(1,n,1);
		sol=max(sol,Maxx);
		x=TT[TT_lant[lant[x]]];
	}
	sol=max(sol,v[lca]);
}

int main()
{
	read();
	DFS(1,0);
	group_init();
	for(int op,x,y,lca,sol;Q;Q--)
	{
		fin>>op>>x>>y;
		if(!op)
		{
			val=v[x]=y;
			poz=what[x];
			update(1,n,1);
			continue;
		}
		sol=0;
		lca=LCA(x,y);
		Val(x,lca,sol);
		Val(y,lca,sol);
		fout<<sol<<'\n';
	}
	
	return 0;
}