#include <algorithm>
#include <iostream>
#include <fstream>
#include <iomanip>
#include <vector>
#include <queue>
#include <stack>

using namespace std;

#define pii pair <int, int>

string filename = "heavypath";

#ifdef LOCAL
    ifstream fin("input.in");
    ofstream fout("output.out");
#else
    ifstream fin(filename + ".in");
    ofstream fout(filename + ".out");
#endif

const int NMAX = 1e5;

int n;
int v[NMAX + 1];
vector <int> adj[NMAX + 1];

int par[NMAX + 1];
int sz[NMAX + 1];
int lvl[NMAX + 1];
int heavy[NMAX + 1];

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

    for(int child : adj[node]){
        if(child != parent){
            explore(child, node);
            sz[node] += sz[child];

            if(sz[child] > sz[heavy[node]]){
                heavy[node] = child;
            }
        }
    }
}

int lin[NMAX + 1];
pii pos[NMAX + 1];

int id[NMAX + 1];
int head[NMAX + 1];

int Id = 0;
int dfsTime = 0;

void heavyfirst(int node, int parent){
    ++dfsTime;
    lin[dfsTime] = node;
    pos[node].first = dfsTime;

    if(heavy[parent] == node){
        id[node] = id[parent];
    }else{
        ++Id;
        id[node] = Id;
        head[Id] = node;
    }

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

    for(int child : adj[node]){
        if(child != parent && child != heavy[node]){
            heavyfirst(child, node);
        }
    }

    pos[node].second = dfsTime;
}

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 query(int x, int y){
    int ans = 0;
    while(id[x] != id[y]){
        if(lvl[head[id[x]]] > lvl[head[id[y]]]){
            ans = max(ans, AINT::query(1, 1, n, pos[head[id[x]]].first, pos[x].first));
            x = par[head[id[x]]];
        }else{
            ans = max(ans, AINT::query(1, 1, n, pos[head[id[y]]].first, pos[y].first));
            y = par[head[id[y]]];
        }
    }
    int a = pos[x].first;
    int b = pos[y].first;
    ans = max(ans, AINT::query(1, 1, n, min(a, b), max(a, b)));
    return ans;
}

signed main(){

    int q;
    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].push_back(b);
        adj[b].push_back(a);
    }

    explore(1, 0);
    heavyfirst(1, 0);

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

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

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

    return 0;
}