#include <fstream>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <map>
#include <set>
#include <stack>
#include <unordered_map>
#include <vector>
#include <string>
#define ll long long

using namespace std;

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

const int NMAX = 1e5;

int n, m, ind;
int values[NMAX + 1];
int sub_tree_size[NMAX + 1];
int heavy[NMAX + 1];
int parent[NMAX + 1];
int depth[NMAX + 1];
int pos[NMAX + 1];
int head[NMAX + 1];
int path[NMAX + 1];
vector<int> G[NMAX + 1];
int aint[4 * NMAX + 1];

void Build(int node, int left, int right) {
    if (left == right) {
        aint[node] = path[left];
        return;
    }

    int mid = (left + right) / 2;
    Build(node * 2, left, mid);
    Build(node * 2 + 1, mid + 1, right);
    aint[node] = max(aint[node * 2], aint[node * 2 + 1]);
}

void Update(int node, int left, int right, int pos, int value) {
    if (left == right) {
        aint[node] = value;
        return;
    }

    int mid = (left + right) / 2;
    if (pos <= mid) {
        Update(node * 2, left, mid, pos, value);
    }
    else {
        Update(node * 2 + 1, mid + 1, right, pos, value);
    }
    aint[node] = max(aint[node * 2], aint[node * 2 + 1]);
}

int Query(int node, int left, int right, int Qleft, int Qright) {
    if (left >= Qleft && right <= Qright) {
        return aint[node];
    }

    int mid = (left + right) / 2;
    if (mid >= Qright) {
        return Query(node * 2, left, mid, Qleft, Qright);
    }
    if (mid + 1 <= Qleft) {
        return Query(node * 2 + 1, mid + 1, right, Qleft, Qright);
    }

    int left_node = Query(node * 2, left, mid, Qleft, Qright);
    int right_node = Query(node * 2 + 1, mid + 1, right, Qleft, Qright);
    return max(left_node, right_node);
}

void DFS(int node = 1, int dad = 0) {
    parent[node] = dad;
    depth[node] = depth[dad] + 1;
    sub_tree_size[node] = 1;

    for (int next_node : G[node]) {
        if (next_node != dad) {
            DFS(next_node, node);
            sub_tree_size[node] += sub_tree_size[next_node];
            if (sub_tree_size[next_node] > sub_tree_size[heavy[node]]) {
                heavy[node] = next_node;
            }
        }
    }
}

void DFSHeavy(int node = 1, int curent_head = 1, int dad = 0) {
    head[node] = curent_head;
    path[++ind] = values[node];
    pos[node] = ind;

    if (heavy[node]) {
        DFSHeavy(heavy[node], curent_head, node);
    }

    for (int next_node : G[node]) {
        if (next_node != dad && next_node != heavy[node]) {
            DFSHeavy(next_node, next_node, node);
        }
    }
}

int Query(int x, int y) {
    int answer = 0;
    while (head[x] != head[y]) {
        if (depth[head[x]] > depth[head[y]]) {
            swap(x, y);
        }
        answer = max(answer, Query(1, 1, ind, pos[head[y]], pos[y]));
        y = parent[head[y]];
    }
    if (depth[x] > depth[y]) {
        swap(x, y);
    }
    answer = max(answer, Query(1, 1, ind, pos[x], pos[y]));
    return answer;
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

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

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

    DFS();
    DFSHeavy();
    Build(1, 1, ind);
    while (m--) {
        int type, x, y;
        cin >> type >> x >> y;
        if (type == 0) {
            Update(1, 1, ind, pos[x], y);
        }
        else {
            cout << Query(x, y) << '\n';
        }
    }

    return 0;
}