#include<fstream>
#include<vector>

#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],split[NMAX];
int level[NMAX],str[18][NMAX],what[NMAX],under[NMAX];
int AINT[(1<<18)],Maxx,K,L,R,poz,val;
int n,Q,v[NMAX],k,TT[NMAX];
short start[NMAX],lant[NMAX];

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

inline 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);
}

void group_init()
{
	for(int i=1,L=1;i<=k;i++)
	{
		start[i]=L;
		TT[i]=split[i][split[i].size()-1];
		for(int j=split[i].size()-1;j>=0;j--,L++)
		{
			val=v[split[i][j]];
			poz=L;
			what[ split[i][j] ]=L;
			update(1,n,1);
		}
		split[i].clear();
	}
}

void ancestors()
{
	for(int i=1;(1<<i)<=n;i++)
		for(int j=1;j<=n;j++)
			str[i][j]=str[i-1][str[i-1][j]];
}

void prep()
{
	DFS(1,0);
	group_init();
	ancestors();
}

void jump(int &x,int &y)
{
	int d=level[x]-level[y];
	for(int step=17,p=(1<<17);step>=0;step--,p>>=1)
		if(d>=p)
		{
			d-=p;
			x=str[step][x];
		}
}

int LCA(int x,int y)
{
	 
	if(level[x]>level[y])
		jump(x,y);
	if(level[x]<level[y])
		jump(y,x);
	if(x==y)
		return x;
	for(int step=17;step>=0;step--)
		if(str[step][x]!=str[step][y])
		{
			x=str[step][x];
			y=str[step][y];
		}
	return str[0][x];
}

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

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