#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;

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

class ST
 {
  public:
    ST(const vector<int> &x)
    {
        for (N = 1; N < int(x.size()); N <<= 1);

        tree = vector<int>(2 * N, 0);
        for (size_t i = 0; i < x.size(); ++i)
            tree[N + i] = x[i];
        for (int i = N - 1; i > 0; --i)
            tree[i] = max(tree[2 * i], tree[2 * i + 1]);
    }

    void Update(int where, const int value)
    {
        tree[where += N] = value;
        for (where >>= 1; where > 0; where >>= 1)
            tree[where] = max(tree[2 * where], tree[2 * where + 1]);
    }

    int Query(int l, int r) const
    {
        l += N;  r += N;
        int vmax = 0;
        while (l <= r)
        {
            vmax = max(vmax, max(tree[l], tree[r]));
            l = (l + 1) / 2;
            r = (r - 1) / 2;
        }
        return vmax;
    }

  private:
    int N;
    vector<int> tree;
};

vector<vector<int> > G, paths;
int V;
vector<int> v, t, nr, h, pId, pos;
vector<ST> st;

void DFS(const int x)
{
    int bs = 0;
    nr[x] = 1;
    for ( const auto& y : G[x] )
    {
        if (y == t[x])
            continue;
        t[y] = x;
        h[y] = h[x] + 1;
        DFS(y);
        nr[x] += nr[y];
        if (bs == 0 || nr[y] > nr[bs])
            bs = y;
    }
    if (bs == 0 )
    {
        pId[x] = int(paths.size());
        paths.push_back(vector<int>());
    }
    else
        pId[x] = pId[bs];

    pos[x] = int(paths[pId[x]].size());
    paths[pId[x]].push_back(x);
}

void BuildHeavyPath()
{
    t = pId = nr = h = pos = vector<int>(V + 1);

    DFS(1);
	for (const auto& path : paths)
	{
        vector<int> pathValues;

        for (int x : path)
            pathValues.push_back(v[x]);

        st.push_back(ST(pathValues));
    }
}

int Query(int x, int y)
{
    if (pId[x] == pId[y])
    {
        if (pos[x] > pos[y])
            swap(x, y);

        return st[pId[x]].Query(pos[x], pos[y]);
    }
    if (h[paths[pId[x]].back()] < h[paths[pId[y]].back()])
        swap(x, y);

    return max(st[pId[x]].Query(pos[x], int(paths[pId[x]].size()) - 1),
                          Query(t[paths[pId[x]].back()], y));
}

int main()
{
    int M;
    fin >> V >> M;
    v = vector<int>(V + 1);
    for (int x = 1; x <= V; ++x)
        fin >> v[x];
    G = vector< vector<int> >(V + 1, vector<int>());
    for (int e = 1; e < V; ++e)
    {
        int x, y;
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    BuildHeavyPath();
    int op, x, y, val;
    while(M)
    {
        M--;
        fin >> op;
        if (op == 0)
        {
            fin >> x >> val;
            v[x] = val;
            st[pId[x]].Update(pos[x], val);
        }
        else
        {
            fin >> x >> y;
			fout << Query(x, y) << "\n";
        }
    }
    fin.close();
    fout.close();
    return 0;
}