#include <iostream>
#include <vector>
#include <math.h>

#define pb push_back

using namespace std;
const int N = 1e5 + 5;

int n, q, timer, clr, lift[N], tin[N], up[N], color[N], subsize[N], v[N], euler[N], aint[4*N];
vector<int> g[N];

void get_size(int nod, int p) {
    subsize[nod] = 1;
    for(auto nxt : g[nod])
        if(nxt != p) {
            get_size(nxt, nod);
            subsize[nod] += subsize[nxt];
        }
}
void dfs(int nod, int p) {
    lift[nod] = p;
    euler[++timer] = nod;
    tin[nod] = timer;
    if(!up[color[nod]])
        up[color[nod]] = nod;

    int maxi = 0;
    for(auto nxt : g[nod])
        if(nxt != p)
            if(subsize[nxt] > subsize[maxi])
                maxi = nxt;
    if(!maxi)
        return;
    color[maxi] = color[nod];
    dfs(maxi, nod);
    for(auto nxt : g[nod])
        if(nxt != p && nxt != maxi) {
            color[nxt] = ++clr;
            dfs(nxt, nod);
        }
}
void build(int nod, int st, int dr) {
    if(st == dr)
        aint[nod] = v[euler[st]];
    else {
        int mid = (st + dr) / 2;
        build(2*nod, st, mid);
        build(2*nod+1, mid+1, dr);

        aint[nod] = max(aint[2*nod], aint[2*nod+1]);
    }
}
void update(int nod, int st, int dr, int pos) {
    if(st == dr)
        aint[nod] = v[euler[st]];
    else {
        int mid = (st + dr) / 2;
        if(pos <= mid)
            update(2*nod, st, mid, pos);
        else
            update(2*nod+1, mid+1, dr, pos);

        aint[nod] = max(aint[2*nod], aint[2*nod+1]);
    }
}
int getmax(int nod, int st, int dr, int l, int r) {
    if(l <= st && dr <= r)
        return aint[nod];
    else {
        int s1 = -1, s2 = -1, mid = (st + dr) / 2;
        if(l <= mid)
            s1 = getmax(2*nod, st, mid, l, r);
        if(mid < r)
            s2 = getmax(2*nod+1, mid+1, dr, l, r);

        return max(s1, s2);
    }
}
int query(int a, int b) {
    int ans = -1;
    while(color[a] != color[b]) {
        if(tin[up[color[a]]] < tin[up[color[b]]])
            swap(a, b);

        ans = max(ans, getmax(1, 1, n, tin[up[color[a]]], tin[a]));
        a = lift[up[color[a]]];
    }
    ans = max(ans, getmax(1, 1, n, min(tin[a], tin[b]), max(tin[a], tin[b])));

    return ans;
}

int main()
{
    freopen("heavypath.in", "r", stdin);
    freopen("heavypath.out", "w", stdout);
    cin.tie(nullptr)->sync_with_stdio(0);

    cin >> n >> q;
    for(int i=1; i<=n; i++)
        cin >> v[i];
    for(int i=1; i<n; i++) {
        int x, y;
        cin >> x >> y;
        g[x].pb(y);
        g[y].pb(x);
    }

    get_size(1, 0);
    color[1] = ++clr;
    dfs(1, 0);
    build(1, 1, n);

    while(q--) {
        int tip, x, y;
        cin >> tip >> x >> y;
        if(tip == 1) {
            cout << query(x, y) << '\n';
        }
        else {
            v[x] = y;
            update(1, 1, n, tin[x]);
        }
    }
    return 0;
}