#include <bits/stdc++.h>

const int NMAX = 1e5 + 5;

int n, Q, a[NMAX], sz[NMAX], aint[4 * NMAX], t[NMAX], nxt[NMAX], pos[NMAX], dep[NMAX];
std :: vector < int > G[NMAX], v;

void DFS(int node, int parent, int depth) {
    t[node] = parent;
    dep[node] = depth;

    for (int i = 0; i < G[node].size(); ++ i) {
        int u = G[node][i];

        if (u != parent) {
            DFS(u, node, depth + 1);
        }
    }

    for (int i = 0; i < G[node].size(); ++ i) {
        int u = G[node][i];

        if (u != parent && sz[G[node][i]] > sz[G[node][0]]) {
            std :: swap(G[node][i], G[node][0]);
        }
    }

    sz[node] = 1;

    for (int i = 0; i < G[node].size(); ++ i) {
        int u = G[node][i];

        if (u != parent) {
            sz[node] += sz[u];
        }
    }

    return;
}

void DFSHeavy(int node, int parent, int newChain) {
    v.push_back(node);
    pos[node] = v.size() - 1;

    if (newChain == true) {
        nxt[node] = node;
    }
    else {
        nxt[node] = nxt[parent];
    }

    int u = G[node][0];

    if (u != parent) {
        DFSHeavy(u, node, false);
    }

    for (int i = 1; i < G[node].size(); ++ i) {
        int u = G[node][i];

        if (u != parent) {
            DFSHeavy(u, node, true);
        }
    }

    return;
}

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

    int mid = ((l + r) >> 1);

    Build(node * 2, l, mid);
    Build(node * 2 + 1, mid + 1, r);

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

    return;
}

void Update(int node, int l, int r, int x, int y) {
    if (l == r) {
        aint[node] = y;
        return;
    }

    int mid = ((l + r) >> 1);

    if (x <= mid) {
        Update(node * 2, l, mid, x, y);
    }
    else {
        Update(node * 2 + 1, mid + 1, r, x, y);
    }

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

    return;
}

int Query(int node, int l, int r, int x, int y) {
    if (r < x || l > y) {
        return 0;
    }

    if (x <= l && r <= y) {
        return aint[node];
    }

    int mid = ((l + r) >> 1);

    return std :: max(Query(node * 2, l, mid, x, y), Query(node * 2 + 1, mid + 1, r, x, y));
}

int calcAns(int x, int y) {
    int ret = 0;

    while (1) {
        if (nxt[x] == nxt[y]) {
            break;
        }

        if (dep[nxt[x]] > dep[nxt[y]]) {
            ret = std :: max(ret, Query(1, 0, n - 1, pos[nxt[x]], pos[x]));

            x = t[nxt[x]];
        }
        else {
            ret = std :: max(ret, Query(1, 0, n - 1, pos[nxt[y]], pos[y]));

            y = t[nxt[y]];
        }
    }

    if (pos[x] > pos[y]) {
        std :: swap(x, y);
    }

    ret = std :: max(ret, Query(1, 0, n - 1, pos[x], pos[y]));

    return ret;
}

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

int main() {
    fin >> n >> Q;

    for (int i = 0; i < n; ++ i) {
        fin >> a[i];
    }

    for (int i = 0, u, v; i < n - 1; ++ i) {
        fin >> u >> v;

        -- u, -- v;

        G[u].push_back(v);
        G[v].push_back(u);
    }

    DFS(0, -1, 0);
    DFSHeavy(0, -1, true);

    Build(1, 0, n - 1);

    while (Q --) {
        int type, x, y;

        fin >> type >> x >> y;

        if (type == 0) {
            -- x;

            Update(1, 0, n - 1, pos[x], y);
        }
        else {
            -- x, -- y;

            fout << calcAns(x, y) << "\n";
        }
    }

    return 0;
}