#include <fstream>
#include <vector>
#include <algorithm>

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;

    for (auto &x : gr[root]) {
        if (used[x]) continue;
        lv[x] = lv[root] + 1;
        int sz = dfs(x);
        if (sz > MAX) {
            MAX = sz;
            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();
        tata_lant[lant[go]] = root;
    }

    return MAX + 1;
}

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

void Update(int nod, int st, int dr, int poz, int v, int ARB) {
    if (st == dr) {
        Arb[ARB][nod] = v;
        return;
    }
    int mij = (st + dr) / 2;
    if (poz <= mij) {
        Update(nod * 2, st, mij, poz, v, ARB);
    } else {
        Update(nod * 2 + 1, mij + 1, dr, poz, v, ARB);
    }
    Arb[ARB][nod] = max(Arb[ARB][nod * 2], Arb[ARB][nod * 2 + 1]);
}

void Query(int nod, int st, int dr, int L, int R, int ARB, int &maxx) {
    if (L > dr || R < st) return;
    if (L <= st && dr <= R) {
        maxx = max(maxx, Arb[ARB][nod]);
        return;
    }
    int mij = (st + dr) / 2;
    Query(nod * 2, st, mij, L, R, ARB, maxx);
    Query(nod * 2 + 1, mij + 1, dr, L, R, ARB, maxx);
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    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);
    }

    lv[1] = 1;
    dfs(1);
    Resize();

    for (int i = 1; i <= n; i++) {
        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]) {
                if (lv[arb[lant[x]].back()] < lv[arb[lant[y]].back()]) {
                    swap(x, y);
                }
                Query(1, 1, arb[lant[x]].size(), pos[x], arb[lant[x]].size(), lant[x], maxx);
                x = tata_lant[lant[x]];
            }
            Query(1, 1, arb[lant[x]].size(), min(pos[x], pos[y]), max(pos[x], pos[y]), lant[x], maxx);
            cout << maxx << '\n';
        }
    }

    return 0;
}