#include <bits/stdc++.h>
#define NM 100005
using namespace std;
ifstream fin ("heavypath.in");
ofstream fout ("heavypath.out");
int n, m, niv[NM], sz[NM], head[NM], t[NM];
int vl[NM], aux[NM], aint[4*NM];
int hv[NM], poz[NM], z;
vector<int> v[NM];
inline void read();
void dfs(int nod)
{
    sz[nod] = 1;
    int max_sz = 0, care;
    for(auto it:v[nod])
        if(it!=t[nod])
        {
            niv[it] = niv[nod] + 1;
            t[it] = nod;
            dfs(it);
            sz[nod]+=sz[it];
            if(sz[it] > max_sz)
            {
                care = it;
                max_sz = sz[it];
            }
        }
    if(max_sz >= sz[nod]/2 && max_sz)
        hv[nod] = care;
}
void build(int nod, int st, int dr)
{
    if(st == dr)
        aint[nod] = vl[st];
    else
    {
        int mijl = (st+dr)/2;
        build(nod*2, st, mijl);
        build(nod*2+1, mijl+1, dr);
        aint[nod] = max(aint[2*nod], aint[2*nod+1]);
    }
}
void update(int nod, int st, int dr, int x, int y)
{
    if(st == dr)
        aint[nod] = y;
    else
    {
        int mijl = (st+dr)/2;
        if(x <= mijl)
            update(nod*2, st, mijl, x, y);
        else
            update(nod*2+1, mijl+1, dr, x, y);
        aint[nod] = max(aint[2*nod], aint[2*nod+1]);
    }
}
int query(int nod, int st, int dr, int x, int y)
{
    if(x <= st && dr <= y)
        return aint[nod];
    else
    {
        int mijl = (st+dr)/2, rez = 0;
        if(x <= mijl)
            rez = max(rez, query(2*nod, st, mijl, x, y));
        if(y >= mijl+1)
            rez = max(rez, query(2*nod+1, mijl+1, dr, x, y));
        return rez;
    }
}
void decompose(int nod, int h)
{
    head[nod] = h;
    vl[++z] = aux[nod];
    poz[nod] = z;
    if(hv[nod])
        decompose(hv[nod], h);
    for(auto it:v[nod])
        if(it!=t[nod] && it!=hv[nod])
            decompose(it, it);
}
int the_query(int x, int y)
{
    int rez = 0;
    for( ;head[x]!=head[y];)
          if(niv[head[x]] > niv[head[y]])
          {
              rez = max(rez, query(1, 1, n, poz[head[x]], poz[x]));
              x = t[head[x]];
          }
          else
          {
              rez = max(rez, query(1, 1, n, poz[head[y]], poz[y]));
              y = t[head[y]];
          }
    rez = max(rez, query(1, 1, n, poz[head[x]], poz[x]));
    rez = max(rez, query(1, 1, n, poz[head[y]], poz[y]));
    return rez;
}
int main()
{
    read();
    dfs(1);
    decompose(1, 1);
    build(1, 1, n);
    while(m--)
    {
        int op, x, y;
        fin >> op >> x >> y;
        if(op == 0)
            update(1, 1, n, poz[x], y);
        else fout << the_query(x, y) << '\n';
    }
    return 0;
}
inline void read()
{
    int x, y;
    fin >> n >> m;
    for(int i=1; i<=n; i++)
        fin >> aux[i];
    for(int i=1; i<n; i++)
    {
        fin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
}