#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
#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 namespace std;
using namespace __gnu_pbds;
 
using ll = long long;
using ld = long double;
using ull = unsigned long long;
 
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(array <T, N> x);
template <class T> 
void wr(vt <T> x);
 
template <class T> 
void wr(T x) {
    cout << x;
}
 
template <class T, class ...M>  void wr(T x, M... args) {
    wr(x), wr(args...);
}
 
template <class T> 
void wr(vt <T> x) {
    for(auto it : x)
        wr(it, ' ');
}
 
template <class T, size_t N>
void wr(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;
}
 
inline 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
}

const int BN = 1e5;
 
struct ST {
    int t[2 * BN];
    int n;
 
    ST() {
 
    }
 
    void init(int _n) {
        n = _n;
        memset(t, 0, sizeof(t));
    }
 
    inline int comb(int l, int r) {
        return max(l, r);
    }
 
    void upd(int p, int v) {
        for(t[p += n] = v;p >>= 1;)
            t[p] = comb(t[p << 1], t[p << 1 | 1]);
    }
 
    int query(int l, int r) {
        ++r;
        int resl = -1, resr = -1;
        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);
    }
};

const int LMX = 17;
int up[17][BN];
int tin[BN], tout[BN];

int timerL = 0;
 
int heavyChild[BN], STpos[BN], chain[BN], par[BN], sz[BN], v[BN];
ST T;
int n, timer = 0;

vt <int> adj[BN];

void dfs(int u, int p) {
    up[0][u] = p;
    tin[u] = ++timerL;
    for (auto& v : adj[u])
        if (v != p) {
            dfs(v, u);
        }
    tout[u] = ++timerL;
}

bool is_ancestor(int u, int v) {
    return tin[u] <= tin[v] and tout[u] >= tout[v];
}

int getLCA(int u, int v) {
    if (is_ancestor(u, v))
        return u;
    if (is_ancestor(v, u))
        return v;

    for (int i = LMX - 1; i >= 0; --i)
        if (!is_ancestor(up[i][u], v))
            u = up[i][u];

    return up[0][u];
}
 
void makeSZ(int u, int p) {
    sz[u] = 1;
    par[u] = p;
    int bestV = -1, Vmx = -1;
    for (int v : adj[u]) {
        if (v == p)
            continue;

        makeSZ(v, u);
        sz[u] += sz[v];
        if (sz[v] > Vmx) {
            Vmx = sz[v];
            bestV = v;
        }
    }

    heavyChild[u] = bestV;
}

void makeHeavy(int u, int p) {
    if (heavyChild[u] != -1) {
        chain[heavyChild[u]] = chain[u];
    }

    for (int v : adj[u]) {
        if (v == p)
            continue;
        makeHeavy(v, u);
    }
}

void setHeavy(int u, int p) {
    STpos[u] = timer++;
    if (heavyChild[u] != -1) {
        setHeavy(heavyChild[u], u);
    }

    for (int v : adj[u])
        if (v != p and v != heavyChild[u]) {
            setHeavy(v, u);
        }
}

void upd(int u, int val) {
    T.upd(STpos[u], val);
}

int queryPath(int u, int p) {
    int res = -1;
    while (chain[u] != chain[p]) {
        res = max(res, T.query(STpos[chain[u]], STpos[u]));
        u = par[chain[u]];
    }
    res = max(res, T.query(STpos[p], STpos[u]));
    return res;
}

int query(int u, int v) {
    int lca = getLCA(u, v);
    return max(queryPath(u, lca), queryPath(v, lca));
}

void init() {
    T.init(n);
 
    for (int u = 0; u < n; ++u) {
        chain[u] = u;
        heavyChild[u] = -1;
    }
 
    makeSZ(0, 0);
    makeHeavy(0, 0);
    setHeavy(0, 0);
 
    for (int i = 0; i < n; ++i) {
        T.upd(STpos[i], v[i]);
    }
}
 
void solve() {
    int q; re(n, q);
    for (int i = 0; i < n; ++i)
        re(v[i]);
    for (int i = 0; i < n - 1; ++i) {
        int u, v; re(u, v);
        --u, --v;
        adj[u].emb(v);
        adj[v].emb(u);
    }

    dfs(0, 0);
    for (int i = 1; i < LMX; ++i)
        for (int j = 0; j < n; ++j)
            up[i][j] = up[i - 1][up[i - 1][j]];

    init();
 
    for (int i = 0; i < q; ++i) {
        int task, u, v; re(task, u, v);
        if (task == 0) {
            --u;
            upd(u, v);
            continue;
        }
        --u, --v;
        wr(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;
}