#include <iostream>
#include <fstream>
#include <vector>

#define vt vector
#define pb push_back
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()

using namespace std;

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

const int NMAX = 1e5;

int n, q;
vt <int> adj[NMAX + 1];
int v[NMAX + 1];

int lvl[NMAX + 1];
int parent[NMAX + 1];
int sub[NMAX + 1];
int heavy[NMAX + 1];

void explore(int node, int par){
    parent[node] = par;
    lvl[node] = lvl[par] + 1;
    sub[node] = 1;

    for(int vec : adj[node]){
        if(vec != par){
            explore(vec, node);
            sub[node] += sub[vec];
        }
    }

    for(int vec : adj[node]){
        if(vec != par){
            if(sub[vec] > sub[heavy[node]]){
                heavy[node] = vec;
            }
        }
    }
}

int ID = 0;
int Id[NMAX + 1];
int head[NMAX + 1];

int Time = 0;
int lin[NMAX + 1];
int pos[NMAX + 1];

void heavy_first(int node, int par){
    ++Time;
    lin[Time] = node;
    pos[node] = Time;

    if(heavy[par] != node){
        head[++ID] = node;
        Id[node] = ID;
    }else{
        Id[node] = Id[par];
    }

    if(heavy[node] != 0){
        heavy_first(heavy[node], node);
    }

    for(int vec : adj[node]){
        if(vec != par && vec != heavy[node]){
            heavy_first(vec, node);
        }
    }
}

namespace AINT{
    int aint[4 * NMAX + 1];

    void build(int node, int l, int r){
        if(l == r){
            aint[node] = v[lin[l]];
            return;
        }

        int mid = (l + r) / 2;
        build(2 * node, l, mid);
        build(2 * node + 1, mid + 1, r);
        
        aint[node] = max(aint[2 * node], aint[2 * node + 1]);
    }

    void update(int node, int l, int r, int pos, int val){
        if(l == r){
            aint[node] = val;
            return;
        }

        int mid = (l + r) / 2;
        if(pos <= mid){
            update(2 * node, l, mid, pos, val);
        }else{
            update(2 * node + 1, mid + 1, r, pos, val);
        }

        aint[node] = max(aint[2 * node], aint[2 * node + 1]);
    }

    int query(int node, int l, int r, int ql, int qr){
        if(ql <= l && r <= qr){
            return aint[node];
        }

        int mid = (l + r) / 2, ans = 0;
        if(ql <= mid){
            ans = max(ans, query(2 * node, l, mid, ql, qr));
        }   
        if(mid + 1 <= qr){
            ans = max(ans, query(2 * node + 1, mid + 1, r, ql, qr));
        }

        return ans;
    }
}

int heavy_query(int a, int b){
    int ans = 0;

    cout << "====================\n";
    while(Id[a] != Id[b]){
        if(lvl[head[Id[a]]] > lvl[head[Id[b]]]){
            //cout << "->> " << pos[a] << ' ' << pos[head[Id[a]]] << endl;
            ans = max(ans, AINT::query(1, 1, n, pos[head[Id[a]]], pos[a]));
            a = parent[head[Id[a]]];
        }else{
            // cout << "-> " << pos[b] << ' ' << pos[head[Id[b]]] << endl;
            // cout << "+ " << b << ' ' << head[Id[b]] << endl;
            ans = max(ans, AINT::query(1, 1, n, pos[head[Id[b]]], pos[b]));
            b = parent[head[Id[b]]];
        }
    }

    ans = max(ans, AINT::query(1, 1, n, min(pos[a], pos[b]), max(pos[a], pos[b])));

    return ans;
}

void solve(){
    fin >> n >> q;

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

    for(int i = 1; i <= n - 1; i++){
        int a, b;
        fin >> a >> b;
        adj[a].pb(b);
        adj[b].pb(a);
    }

    explore(1, 0);
    heavy_first(1, 0);

    AINT::build(1, 1, n);

    // for(int i = 1; i <= n; i++){
    //     cout << ">> " << i << ' ' << pos[i] << ' ' << Id[i] << ' ' << head[Id[i]] << '\n';
    // }
    // for(int i = 1; i <= n; i++){
    //     cout << lin[i] << ' ';
    // }
    // cout << '\n';

    while(q--){
        int type;
        fin >> type;

        if(type == 0){
            int node, val;
            fin >> node >> val;
            AINT::update(1, 1, n, pos[node], val);
        }else{
            int x, y;
            fin >> x >> y;
            fout << heavy_query(x, y) << '\n';
        }
    }
}

int main(){

    int T;
    // fin >> T;

    T = 1;

    while(T--){
        solve();
    }

    return 0;
}