#include <fstream>
#include <vector>

using namespace std;

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

const int N = 1e5;
int a[N + 1], siz[N + 1], heavy_son[N + 1], head[N + 1], t[N + 1], l[N + 1], chain[N + 1], h[N + 1], dad[N + 1];

vector <int> g[N + 1];

int n, m, x, y, cer, lant, timp;

void dfs (int node, int tata)
{
    siz[node] = 1;
    h[node] = h[tata] + 1;
    dad[node] = tata;
    for (auto it : g[node])
        if (it != tata)
        {
            dfs (it, node);
            siz[node] += siz[it];
            if (siz[it] > siz[heavy_son[node]])
                heavy_son[node] = it;
        }
}

void dfs_first (int node, int tata)
{
    ++timp;
    t[timp] = node;
    l[node] = timp;
    if (heavy_son[tata] != node)
    {
        head[++lant] = node;
        chain[node] = lant;
    }
    else
    {
        chain[node] = lant;
    }
    if (heavy_son[node])
        dfs_first (heavy_son[node], node);
    for (auto it : g[node])
        if (it != tata && it != heavy_son[node])
            dfs_first (it, node);
}

struct aint
{
    int arb[4 * N + 1];
    aint ()
    {
        for (int i = 1; i <= 4 * N; ++i)
            arb[i] = 0;
    }
    void build (int node, int l, int r)
    {
        if (l == r)
        {
            arb[node] = a[t[l]];
            return;
        }
        int med = (l + r) >> 1;
        build (node << 1, l, med);
        build (node << 1 | 1, med + 1, r);
        arb[node] = max (arb[node << 1], arb[node << 1 | 1]);
    }
    void update (int node, int l, int r, int poz, int val)
    {
        if (l == r)
        {
            arb[node] = val;
            return;
        }
        int med = (l + r) >> 1;
        if (poz <= med)
            update (node << 1, l, med, poz, val);
        else
            update (node << 1 | 1, med + 1, r, poz, val);
        arb[node] = max (arb[node << 1], arb[node << 1 | 1]);
    }
    int query (int node, int l, int r, int st, int dr)
    {
        if (l >= st && r <= dr)
            return arb[node];
        int med = (l + r) >> 1;
        int a1, a2;
        a1 = a2 = 0;
        if (st <= med)
            a1 = query (node << 1, l, med, st, dr);
        if (dr > med)
            a2 = query (node << 1 | 1, med + 1, r, st, dr);
        return max (a1, a2);
    }
} v;

int solve(int x, int y)
{
    int ans = 0;
    while (chain[x] != chain[y])
    {
        int headx = head[chain[x]];
        int heady = head[chain[y]];
        if (h[headx] > h[heady])
        {
            ans = max (ans, v.query(1, 1, n, l[headx], l[x]));
            x = dad[headx];
        }
        else
        {
            ans = max (ans, v.query(1, 1, n, l[heady], l[y]));
            y = dad[heady];
        }
    }
    ans = max (ans, v.query (1, 1, n, min (l[x], l[y]), max(l[x], l[y])));
    return ans;
}

int main()
{
    cin >> n >> m;
    for (int i = 1; i <= n; ++i)
        cin >> a[i];
    for (int i = 1; i < n; ++i)
    {
        cin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs (1, 0);
    dfs_first(1, 0);
    v.build (1, 1, n);
    for (int i = 1; i <= m; ++i)
    {
        cin >> cer >> x >> y;
        if (!cer)
        {
            v.update (1, 1, n, l[x], y);
            a[x] = y;
        }
        else
        {
            cout << solve(x, y) << '\n';
        }
    }
    return 0;
}