#include<cstdio>
#include<fstream>
#include<iostream>
#include<iomanip>
#include<algorithm>
#include<vector>
#include<bitset>
#include<deque>
#include<queue>
#include<set>
#include<map>
#include<cmath>
#include<cstring>
#include<ctime>
#include<cstdlib>
#include<unordered_map>

#define ll long long
#define pb push_back
#define mp make_pair
#define pii pair<int,int>
#define pll pair<ll,ll>
#define all(x) (x).begin(), (x).end()
#define fi first
#define se second

using namespace std;

const int nmax = 100005;

int n, m, i, x, y, paths, poz, val, op, a, b, sol;
int lev[nmax], f[nmax], cost[nmax], sub[nmax];
int sz[nmax], lant[nmax], where[nmax];

vector<int> v[nmax], p[nmax], seg[nmax];

void dfs(int x, int d)
{
    sub[x] = 1;

    for(auto it : v[x])
        if(it != d)
        {
            lev[it] = lev[x] + 1;
            f[it] = x;
            dfs(it, x);
            sub[x] += sub[it];
        }

    if(v[x].size() == 1 && x != 1)
    {
        lant[x] = ++paths;
        p[paths].pb(0);
        p[paths].pb(x);
        where[x] = ++sz[paths];
        return;
    }

    int maxi = 0;
    for(auto it : v[x])
        if(it != d && sub[it] > sub[maxi])
            maxi = it;

    lant[x] = lant[maxi];
    p[lant[x]].pb(x);
    where[x] = ++sz[lant[x]];
}

void build(int node, int l, int r, int path)
{
    if(l == r)
    {
        seg[path][node] = cost[p[path][l]];
        return;
    }

    int mi = (l + r) / 2;
    int ls = 2 * node;
    int rs = 2 * node + 1;

    build(ls, l, mi, path);
    build(rs, mi + 1, r, path);

    seg[path][node] = max(seg[path][ls], seg[path][rs]);
}

void update(int node, int l, int r, int poz, int val, int path)
{
    if(l == r)
    {
        seg[path][node] = val;
        return;
    }

    int mi = (l + r) / 2;
    int ls = 2 * node;
    int rs = 2 * node + 1;

    if(poz <= mi)
        update(ls, l, mi, poz, val, path);
    else
        update(rs, mi + 1, r, poz, val, path);

    seg[path][node] = max(seg[path][ls], seg[path][rs]);
}

void query(int node, int l, int r, int a, int b, int path)
{
    if(l >= a && r <= b)
    {
        sol = max(sol, seg[path][node]);
        return;
    }

    int mi = (l + r) / 2;
    int ls = 2 * node;
    int rs = 2 * node + 1;

    if(a <= mi)
        query(ls, l, mi, a, b, path);
    if(b > mi)
        query(rs, mi + 1, r, a, b, path);
}

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", &cost[i]);

    for(i = 1; i < n; i++)
    {
        scanf("%d%d", &x, &y);
        v[x].pb(y);
        v[y].pb(x);
    }

    dfs(1, 0);

    for(i = 1; i <= paths; i++)
    {
        reverse(p[i].begin() + 1, p[i].end());
        seg[i].resize(4 * sz[i] + 5);
        build(1, 1, sz[i], i);
    }

    for(i = 1; i <= n; i++)
        where[i] = sz[lant[i]] + 1 - where[i];

    for(; m; m--)
    {
        scanf("%d", &op);

        if(op == 0)
        {
            scanf("%d%d", &x, &val);
            poz = where[x];
            update(1, 1, sz[lant[x]], poz, val, lant[x]);
        }
        else
        {
            scanf("%d%d", &x, &y);

            sol = 0;
            for(;;)
            {
                if(lant[x] == lant[y])
                {
                    a = min(where[x], where[y]);
                    b = max(where[x], where[y]);
                    query(1, 1, sz[lant[x]], a, b, lant[x]);
                    break;
                }

                if(lev[p[lant[x]][1]] < lev[p[lant[y]][1]])
                    swap(x, y);

                a = 1;
                b = where[x];
                query(1, 1, sz[lant[x]], a, b, lant[x]);
                x = f[p[lant[x]][1]];
            }

            printf("%d\n", sol);
        }
    }

    return 0;
}