#include <bits/stdc++.h>
using namespace std;

#define pb push_back
#define dbg(x) cout << #x <<": " << x << "\n";
#define sz(x) ((int)x.size())

using ll = long long;

const string fn = "heavypath";
ifstream fin(fn + ".in");
ofstream fout(fn + ".out");

const int mxn = 100005;

int n, qs;
int posac;


int pos[mxn];
int head[mxn];
int heavy[mxn];
int depth[mxn];
int value[mxn];
int parent[mxn];

int subarbSz[mxn];

vector<int> g[mxn];

int a[4 * mxn];
int valAtPos[mxn];
void build(int nod, int st, int dr) {
    if (st == dr) {
        a[nod] = valAtPos[st];
    }
    else {
        int mid = (st + dr) >> 1;
        build(nod << 1, st, mid);
        build(nod << 1 | 1, mid + 1, dr);
        a[nod] = max(a[nod << 1], a[nod << 1 | 1]);
    }

}

void upd(int nod, int st, int dr, int p, int val) {

    if (st == dr) {
        a[nod] = val;
    }
    else {
        int mid = (st + dr) >> 1;
        if (p <= mid)
            upd(nod << 1, st, mid, p, val);
        else
            upd(nod << 1 | 1, mid + 1, dr, p, val);
        a[nod] = max(a[nod << 1], a[nod << 1 | 1]);
    }

}

int qry(int nod, int st, int dr, int x, int y) {
    if (st > dr || st > y || dr < x)
        return -1;
    if (st >= x && dr <= y)
        return a[nod];
    int mid = (st + dr) >> 1;
    int q1 = qry(nod << 1, st, mid, x, y);
    int q2 = qry(nod << 1 | 1, mid + 1, dr, x, y);
    return max(q1, q2);
}

int aintQry(int x, int y) {
    return qry(1, 1, n, x, y);
}



void dfs(int nod) {
    int acSz = 1;
    int maxSonSz = 0;
    for (int fiu : g[nod])
        if (fiu != parent[nod]) {
            parent[fiu] = nod;
            depth[fiu] = depth[nod] + 1;
            dfs(fiu);
            acSz += subarbSz[fiu];
            if (subarbSz[fiu] > maxSonSz) {
                maxSonSz = subarbSz[fiu];
                heavy[nod] = fiu;
            }
        }
    subarbSz[nod] += acSz;
}

void decompose(int nod, int best) {
    head[nod] = best;
    pos[nod] = ++posac;
    if (heavy[nod] != -1)
        decompose(heavy[nod], best);
    for (auto fiu : g[nod])
        if (fiu != heavy[nod] && fiu != parent[nod])
            decompose(fiu, fiu);

}

int qryDecomp(int x, int y) {
    int ans = 0;
    while (head[x] != head[y]) {
        if (depth[head[x]] > depth[head[y]])
            swap(x, y);
        ans = max(ans, aintQry(pos[head[y]], pos[y]));
        y = parent[head[y]];
    }
    if (depth[x] > depth[y])
        swap(x, y);
    ans = max(ans, aintQry(pos[x], pos[y]));
    return ans;
}

int main() {

    fin >> n >> qs;

    for (int i = 1; i <= n; ++i) {
        fin >> value[i];
        heavy[i] = -1;
    }
    for (int i = 1; i < n; ++i) {
        int x, y;
        fin >> x >> y;
        g[x].pb(y);
        g[y].pb(x);
    }
    parent[1] = 1;
    dfs(1);
    decompose(1, 1);

    for (int i = 1; i <= n; ++i)
        valAtPos[pos[i]] = value[i];
    build(1, 1, n);

    while (qs--) {
        int op, x, y;
        fin >> op >> x >> y;
        if (op == 0) {
            value[x] = y;
            upd(1, 1, n, pos[x], y);
        }
        else {
            fout << qryDecomp(x, y) << '\n';
        }
    }

    return 0;
}