#include<cstdio>
#include<cstring>
#include<vector>
using namespace std;
const int M=100001;
int n,m,t,x,y,z,nrchain,i,nr,j,k;
int v[M],h[M],s[M],ind[M],poz[M],nodes[M],pLant[M],arb[2*M];
vector<int> l[M],chain[M];
bool viz[M];
void D(int x,int p)
{
	int best=0,i,j;
	h[x]=h[p]+1,s[x]=1;
	for(j=l[x].size(),i=0;i<j;++i)
		if(l[x][i]!=p)
		{
			D(l[x][i],x),s[x]+=s[l[x][i]];
			if(s[best]<s[l[x][i]])
				best=l[x][i];
		}
	for(i=0;i<j;++i)
		if(l[x][i]!=p&&l[x][i]!=best)
			pLant[ind[l[x][i]]]=x;
	if(!best)
		ind[x]=++nrchain;
	else
		ind[x]=ind[best];
	chain[ind[x]].push_back(x);
}
void U(int pos,int val)
{
	pos+=n,arb[pos]=val;
	for(;pos>1;pos>>=1)
		arb[pos>>1]=max(arb[pos],arb[pos^1]);
}
int Q(int x,int y)
{
	int res = 0;
	for(x+=n,y+=n;x<y;x>>=1,y>>=1)
	{
		if(x&1)
			res=max(res,arb[x++]);
		if(y&1)
			res=max(res,arb[--y]);
	}
	return res;
}
int H(int x,int y)
{
	int res=0;
	while(ind[x]!=ind[y])
	{
		if(h[pLant[ind[x]]]<h[pLant[ind[y]]])
			swap(x,y);
		res=max(res,Q(poz[x],poz[chain[ind[x]].back()]+1)),x=pLant[ind[x]];
	}
	if(poz[x]>poz[y])
		swap(x,y);
	return max(res,Q(poz[x],poz[y]+1));
}
int main()
{
	freopen("heavypath.in","r",stdin),freopen("heavypath.out","w",stdout),scanf("%d%d",&n,&m);
	for(i=1;i<=n;++i)
		scanf("%d",v+i);
	for(i=0;i<n-1;++i)
		scanf("%d%d",&x,&y),l[x].push_back(y),l[y].push_back(x);
	for(D(1,0),i=1;i<=nrchain;++i)
		for(k=chain[i].size(),j=0;j<k;++j)
			poz[chain[i][j]]=++nr,nodes[nr]=chain[i][j],arb[nr+n]=v[chain[i][j]];
	for(i=n;i;--i)
		arb[i]=max(arb[2*i],arb[2*i+1]);
	for(i=0;i<m;i++)
	{
		scanf("%d%d%d",&t,&x,&y);
		if(!t)
			U(poz[x],y);
		else if(t==1)
			printf("%d\n",H(x,y));
	}
}