#include <fstream>
#include <vector>
using namespace std;

ifstream cin("heavypath.in");
ofstream cout("heavypath.out");

vector<int> v[100001];
int a[100001],n;
int t1[200001];
int t[100001];
int urm[100001];
int mar[100001];
int par[100001];
int adan[100001],cnt;

void update(int poz,int val){
    poz+=n;
    t1[poz]=val;
    while(poz>1){
        t1[poz/2]=max(t1[poz],t1[poz^1]);
        poz/=2;
    }
}

int query(int st,int dr){
    int rasp=0;
    st+=n;dr+=n;
    while(st<dr){
        if(st%2){
            rasp=max(rasp,t1[st]);st++;
        }
        if(dr%2){
            dr--;rasp=max(rasp,t1[dr]);
        }st/=2;dr/=2;
    }
    return rasp;
}

void dfs(int tata,int nod){
    mar[nod]=1;adan[nod]=adan[tata]+1;
    par[nod]=tata;
    for(auto &it:v[nod]){
        if(it==tata) continue;
        dfs(nod,it);
        mar[nod]+=mar[it];
        if(v[nod][0]==tata || mar[it]>mar[v[nod][0]]) swap(v[nod][0],it);
    }
}

void dfs1(int tata,int nod){
    t[nod]=cnt;cnt++;
    for(auto it:v[nod]){
        if(it==tata) continue;
        if(it==v[nod][0]) urm[it]=urm[nod];
        else urm[it]=it;
        dfs1(nod,it);
    }
}

int query1(int a1,int b1){
    int rasp=0;
    while(urm[a1]!=urm[b1]){
        if(adan[urm[a1]]<adan[urm[b1]]) swap(a1,b1);
        rasp=max(rasp,query(t[urm[a1]],t[a1]+1));
        a1=par[urm[a1]];
    }
    if(adan[a1]>adan[b1]) swap(a1,b1);
    return max(rasp,query(t[a1],t[b1]+1));
}

int main()
{
    int i,q,a1,b1,cer;
    cin>>n>>q;
    for(i=1;i<=n;i++) cin>>a[i];
	for(i=1;i<n;i++){
        cin>>a1>>b1;
        v[a1].push_back(b1);
        v[b1].push_back(a1);
	}
	dfs(-1,1);
	urm[1]=1;
	dfs1(-1,1);
	for(i=1;i<=n;i++){
        update(t[i],a[i]);
	}
	for(i=1;i<=q;i++){
        cin>>cer>>a1>>b1;
        if(!cer) update(t[a1],b1);
        else cout<<query1(a1,b1)<<"\n";
	}
    return 0;
}