#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

#define ar array
#define vt vector
#define pq priority_queue
#define pu push
#define pub push_back
#define em emplace
#define emb emplace_back
#define mt make_tuple

#define all(x) x.begin(), x.end()
#define allr(x) x.rbegin(), x.rend()
#define allp(x, l, r) x.begin() + l, x.begin() + r
#define len(x) (int)x.size()
#define uniq(x) unique(all(x)), x.end()

using ll = long long;
using ld = long double;
using ull = unsigned long long;

template<class Fun> class y_combinator_result {
    Fun fun_;
public:
    template<class T> explicit y_combinator_result(T &&fun): fun_(std::forward<T>(fun)) {}
    template<class ...Args> decltype(auto) operator()(Args &&...args) { return fun_(std::ref(*this), std::forward<Args>(args)...); }
};
template<class Fun> decltype(auto) y_combinator(Fun &&fun) { return y_combinator_result<std::decay_t<Fun>>(std::forward<Fun>(fun)); }
template <class T, size_t N>

void re(array <T, N>& x);
template <class T> 
void re(vt <T>& x);

template <class T> 
void re(T& x) {
    cin >> x;
}

template <class T, class... M> 
void re(T& x, M&... args) {
    re(x), re(args...);
}

template <class T> 
void re(vt <T>& x) {
    for(auto& it : x) re(it);
}

template <class T, size_t N>
void re(array <T, N>& x) {
    for(auto& it : x) re(it);
}

template <class T, size_t N>
void wr(const array <T, N>& x);
template <class T> 
void wr(const vt <T>& x);

template <class T> 
void wr(const T& x) {
    cout << x;
}

template <class T, class ...M>  
void wr(const T& x, const M&... args) {
    wr(x), wr(args...);
}

template <class T> 
void wr(const vt <T>& x) {
    for(auto it : x) wr(it, ' ');
}

template <class T, size_t N>
void wr(const array <T, N>& x) {
    for(auto it : x) wr(it, ' ');
}

template<class T, class... M>
auto mvt(size_t n, M&&... args) {
    if constexpr(sizeof...(args) == 1)
        return vector<T>(n, args...);
    else
        return vector(n, mvt<T>(args...));
}

void set_fixed(int p = 0) {
    cout << fixed << setprecision(p);
}

void set_scientific() {
    cout << scientific;
}

void Open(const string& name) {
#ifndef ONLINE_JUDGE
    (void)!freopen((name + ".in").c_str(), "r", stdin);
    (void)!freopen((name + ".out").c_str(), "w", stdout);
#endif
}

struct ST {
    vt <int> t;
    int n;

    ST() {}
    ST(int _n) {
        n = _n;
        t = vt <int>(2 * n, -1);
    }

    void init(int _n) {
        n = _n;
        t = vt <int>(2 * n, -1);
    }

    inline int comb(int l, int r) {
        return max(l, r);
    }

    void build(vt <int>& a) {
        for(int i = 0;i < n;i++)
            t[i + n] = a[i];
        for (int i = n - 1;i > 0;i--)
            t[i] = comb(t[i << 1], t[i << 1 | 1]);
    }

    void upd(int p, int v) {
        --p;
        for(t[p += n] = v;p >>= 1;)
            t[p] = comb(t[p << 1], t[p << 1 | 1]);
    }

    int query(int l, int r) {
        int resl = -1, resr = -1;
        --l;
        for(l += n, r += n;l < r;l >>= 1, r >>= 1) {
            if(l & 1) resl = comb(resl, t[l++]);
            if(r & 1) resr = comb(t[--r], resr);
        }
        return comb(resl, resr);
    }
};
 
struct HPD {
    vt <int> heavyChild, STpos, chain, depth, par, v;
    vt <vt <int>> adj;
    ST T;
    int n, timer = 0;
 
    void init(int _n, const vt <vt <int>>& _adj, vt <int> _v) {
        n = _n, v = _v, adj = _adj;
 
        heavyChild.assign(n, 0);
        STpos.assign(n, 0);
        chain.assign(n, 0);
        depth.assign(n, 0);
        par.assign(n, 0);
 
        T.init(n);
        for (int u = 0; u < n; ++u) {
            chain[u] = u;
            heavyChild[u] = -1;
        }
 
        makeSZ(0);
        decompose(0, 0);
 
        for (int i = 0; i < n; ++i) {
            T.upd(STpos[i], v[i]);
        }
    }
 
    int makeSZ(int u, int p = 0) {
        par[u] = p;
        int sz = 1, mx_sz = 0;
        for (auto& v : adj[u]) {
            if (v == p)
                continue;
            
            depth[v] = depth[u] + 1;
            int v_sz = makeSZ(v, u);
            sz += v_sz;  
            if (v_sz > mx_sz) {
                mx_sz = v_sz;
                heavyChild[u] = v;
            }
        }
        return sz;
    }

    void decompose(int u, int h) {
        chain[u] = h;
        STpos[u] = ++timer; // modify to timer++ when using normal segment tree
        if (heavyChild[u] != -1) {
            decompose(heavyChild[u], h);
        }

        for (auto& v : adj[u])
            if (v != par[u] and v != heavyChild[u]) {
                decompose(v, v);
            }
    }
 
    void upd(int u, int val) {
        T.upd(STpos[u], val);
    }
 
    int query(int u, int v) {
        int res = -1;
        while (chain[u] != chain[v]) {
            if (depth[chain[u]] > depth[chain[v]])
                swap(u, v);

            res = max(res, T.query(STpos[chain[v]], STpos[v]));
            v = par[chain[v]];
        }

        if (depth[u] > depth[v]) {
            swap(u, v);
        }
        res = max(res, T.query(STpos[u], STpos[v]));
        return res;
    }
};

void solve() {
    int n, q; re(n, q);
    vt <int> v(n); re(v);
    vt <vt <int>> adj(n);
    for (int i = 1; i < n; ++i) {
        int u, v; re(u, v);
        --u, --v;
        adj[u].emb(v);
        adj[v].emb(u);
    }

    HPD T;
    T.init(n, adj, v);
 
    for (int i = 0; i < q; ++i) {
        int task, u, v; re(task, u, v);
        if (task == 0) {
            --u;
            T.upd(u, v);
            continue;
        }
        --u, --v;
        wr(T.query(u, v), '\n');
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    Open("heavypath");

    int t = 1;
    for(;t;t--) {
        solve();
    }
    
    return 0;
}