#include <fstream>
#include <vector>

using namespace std;

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

int val [100100];

vector < vector < int > > gr (100100);
vector < bool > used (100100);

vector < vector < int > > arb (100100);
vector < vector < int > > Arb (100100);
vector < int > tata_lant (100100);
vector < int > lant (100100);
vector < int > lv (100100);
vector < int > pos (100100);
int cont = 0;

int dfs(int root){

    used[root] = true;
    int MAX = 0;
    int go = 0;
    int last = 0;

    for (auto &x : gr[root]){
        if (used[x]){
            last = x;
            continue;
        }
        lv[x] = lv[root] + 1;
        int val = dfs(x);
        if (MAX < val){
            MAX = val;
            go = x;
        }
    }

    if (go == 0){
        cont++;
        arb[cont].push_back(root);
        lant[root] = cont;
        pos[root] = 1;
    }

    else{
        arb[lant[go]].push_back(root);
        lant[root] = lant[go];
        pos[root] = arb[lant[root]].size();
        for (auto &x : gr[root]){
            if (x == last || x == go){
                continue;
            }
            tata_lant [lant[x]] = root;
        }
    }

    return MAX + 1;

}

void Resize(){

    for (int i=1; i<=cont; i++){
        Arb[i].resize(arb[i].size() * 4);
    }

}

void Update (int nod , int st , int dr , int poz , int val , int ARB){

    if (st == dr){
        Arb[ARB][nod] = val;
        return;
    }

    int mij = st + dr;
    mij /= 2;

    if (mij >= poz){
        Update(nod * 2 , st , mij , poz , val , ARB);
    }
    else{
        Update(nod * 2 + 1 , mij + 1 , dr , poz , val , ARB);
    }

    Arb[ARB][nod] = max ( Arb[ARB][nod * 2] , Arb[ARB][nod * 2 + 1] );

}

void Querry (int nod , int st , int dr , int MIN , int MAX , int ARB , int &maxx){

    if (MIN <= st && MAX >= dr){
        maxx = max ( maxx , Arb[ARB][nod] );
        return;
    }

    int mij = st + dr;
    mij /= 2;

    if (mij >= MIN){
        Querry (nod * 2 , st , mij , MIN , MAX , ARB , maxx);
    }
    if (mij < MAX){
        Querry (nod * 2  + 1, mij + 1 , dr , MIN , MAX , ARB , maxx);
    }

}

int main() {

    ios::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    int n , m;
    cin>>n>>m;

    for (int i=1; i<=n; i++){
        cin>>val[i];
    }

    for (int i=1; i<n; i++){
        int a , b;
        cin>>a>>b;
        gr[a].push_back(b);
        gr[b].push_back(a);
    }

    dfs(1);

    /*for (int i=1; i<=cont; i++){
        cout<<i<<" :  ";
        for (auto &x : arb[i]){
            cout<<x<<" ";
        }
        cout<<'\n';

        cout<<"nod tata -> "<<tata_lant[i]<<'\n';
        cout<<"lant tata -> "<<lant[tata_lant[i]]<<'\n';
        cout<<"lv -> "<<lv[arb[i][arb[i].size() - 1]]<<'\n';
        cout<<'\n';
    }
    cout<<"------------------------------------"<<'\n'<<'\n';*/

    Resize();

    for (int i=1; i<=n; i++){
        //cout<<i<<" : "<<val[i]<<" "<<lant[i]<<" "<<pos[i]<<" "<<lv[i]<<'\n';
        Update (1 , 1 , arb[lant[i]].size() , pos[i] , val[i] , lant[i]);
    }


    for (int i=1; i<=m; i++){
        int test , x , y;
        cin>>test>>x>>y;

        if (test == 0){
            val[x] = y;
            Update (1 , 1 , arb[lant[x]].size() , pos[x] , val[x] , lant[x]);
        }

        else{
            int maxx = 0;
            while ( lant[x] != lant[y] ){

                int lv_x = lv [ arb [lant[x]] [arb [ lant[x] ].size() - 1 ]];
                int lv_y = lv [ arb [lant[y]] [arb [ lant[y] ].size() - 1 ]];

                if (lv_x > lv_y){
                    Querry(1, 1 , arb[lant[x]].size() , pos[x] , arb[lant[x]].size() , lant[x] , maxx);
                    x = tata_lant[lant[x]];
                }
                else{
                    Querry(1, 1 , arb[lant[y]].size() , pos[y] , arb[lant[y]].size() , lant[y] , maxx);
                    y = tata_lant[lant[y]];
                }

            }
            Querry(1, 1 , arb[lant[x]].size() , min(pos[x] , pos[y]) , max(pos[x] , pos[y]) , lant[x] , maxx);

            cout<<maxx<<'\n';

        }

    }

    return 0;
}