#include <fstream>
#include <list>
#include <vector>
using namespace std;
vector<int>G[100010];
list<int>L[100010];
bool viz[100010];
int arb[1000010], Level[100010], fii[100010], Path[100010], Front[100010], v[100010], Dim[100010];
int N, p, val, x, y, a, b, sol, n, m, i, j, t, Paths, Pos[100010], tata[100010];
list<int>::iterator itl;
void update(int Which, int nod, int l, int r)
{
if(l == r)
{
arb[Which+nod] = val;
return;
}
int m = (l+r)/2;
if(x <= m) update(Which, 2*nod, l, m);
if(x > m) update(Which, 2*nod+1, m+1, r);
arb[Which + nod] = max(arb[Which + 2*nod], arb[Which + 2*nod+1]);
}
void query(int Which, int nod, int l, int r)
{
if(l >= a and r <= b)
{
sol = max(sol, arb[Which+nod]);
return;
}
int m = (l+r)/2;
if(a <= m) query(Which, 2*nod, l, m);
if(b > m) query(Which, 2*nod+1, m+1, r);
}
void HeavyPath(int x, int level)
{
int lant = 0;
vector<int>::iterator it;
Level[x] = level;
viz[x] = 1;
fii[x] = 1;
for(it = G[x].begin(); it != G[x].end(); ++it)
if(!viz[*it])
{
tata[*it] = x;
HeavyPath(*it, level+1);
fii[x] += fii[*it];
if(fii[*it] > fii[lant]) lant = *it;
}
if(!lant)
Path[x] = ++Paths;
else
Path[x] = Path[lant];
L[Path[x]].push_front(x);
Front[Path[x]] = x;
}
int main()
{
ifstream fi("heavypath.in");
ofstream fo("heavypath.out");
fi >> n >> m;
for(i = 1; i <= n; i++) fi >> v[i];
for(i = 1; i < n; i++)
{
fi >> x >> y;
G[x].push_back(y);
G[y].push_back(x);
}
HeavyPath(1, 1);
for(i = 1; i <= Paths; i++)
{
N = L[i].size();
Dim[i] = Dim[i-1] + 4*N;
for(itl = L[i].begin(), p = 1; itl != L[i].end(); ++itl, ++p)
{
Pos[*itl] = p;
val = v[*itl]; x = p;
update(Dim[i-1], 1, 1, N);
}
}
while(m--)
{
fi >> t >> x >> y;
if(t == 0)
{
i = Path[x];
val = y;
N = L[i].size();
update(Dim[i-1], 1, 1, N);
}
else
{
sol = 0;
while(Path[x] != Path[y])
{
i = Path[x]; j = Path[y];
if(Level[Front[i]] < Level[Front[j]])
{
swap(x, y);
swap(i, j);
}
a = 1; b = Pos[x];
N = L[i].size();
query(Dim[i-1], 1, 1, N);
x = tata[Front[i]];
}
if(Pos[x] > Pos[y]) swap(x, y);
a = Pos[x]; b = Pos[y];
i = Path[x]; N = L[i].size();
query(Dim[i-1], 1, 1, N);
fo << sol << "\n";
}
}
return 0;
}