#include <bits/stdc++.h>
#define n_max 100000
 
using namespace std;
ifstream f("heavypath.in");
ofstream g("heavypath.out");
int n, m, pos;
int val[n_max + 5], heavy[n_max + 5], t[n_max + 5], nivel[n_max + 5], size[n_max + 5], lant[n_max + 5], poz[n_max + 5], arb[4 * n_max + 5];
vector<int> graf[n_max + 5];

void Read()
{
  f>>n>>m;
  for(int i = 1;i <= n;++i)
    f>>val[i];
  int x, y;
  for(int i = 1;i < n;++i)
    f>>x>>y, graf[x].push_back(y), graf[y].push_back(x);
}

void dfs(int nod, int parinte)
{
  size[nod] = 1;
  nivel[nod] = nivel[parinte] + 1;
  t[nod] = parinte;
  int maxim = 0;
  for(auto it : graf[nod])
    if(it != parinte)
      {
        dfs(it, nod);
        size[nod] += size[it];
        if(maxim < size[it])
          maxim = size[it], heavy[nod] = it;
      }
}

void decompose(int nod, int sus)
{
  lant[nod] = sus, poz[nod] = ++pos;  
  if(heavy[nod])
    decompose(heavy[nod], sus);
  for(auto it : graf[nod])
    if(it != t[nod] && it != heavy[nod])
      decompose(it, it);
}

void update(int nod, int st, int dr, int upos, int val)
{
  if(upos < st || upos > dr)
    return;
  if(st == dr)
  {
    arb[nod] = val;
    return;
  }
  int mid = (st + dr) / 2;
  update(2 * nod, st, mid, upos, val);
  update(2 * nod + 1, mid + 1, dr, upos, val);
  arb[nod] = max(arb[2 * nod], arb[2 * nod + 1]);
}

int query(int nod, int st, int dr, int start, int finish)
{
  if(start > dr || finish < st || st > dr)
    return 0;
  if(start <= st && dr <= finish)
    return arb[nod];
  int mid = (st + dr) / 2;
  return max(query(2 * nod, st, mid, start, finish), query(2 * nod + 1, mid + 1, dr, start, finish));
}

int query_all(int x, int y)
{
  int rez = 0;
  while(lant[x] != lant[y])
  {
    if(nivel[lant[x]] < nivel[lant[y]])
      swap(x, y);
    rez = max(rez, query(1, 1, n, poz[lant[x]], poz[x]));
    x = t[lant[x]];
  }
  if(nivel[x] < nivel[y])
    swap(x, y);
  rez = max(rez, query(1, 1, n, poz[y], poz[x]));
  return rez;
}

void Solve()
{
  dfs(1, 0);
  decompose(1, 1);
  for(int i = 1;i <= n;++i)
    update(1, 1, n, poz[i], val[i]);
  int t, x, y;
  for(int i = 1;i <= m;++i)
    {
      f>>t>>x>>y;
      if(!t)
        update(1, 1, n, poz[x], y);
      else
        g<<query_all(x, y)<<'\n';
    }
}

int main()
{
  Read();
  Solve();
  return 0;
}