#include <bits/stdc++.h>

using namespace std;
ifstream f("heavypath.in");
ofstream g("heavypath.out");
int max_fiu[100005],niv[100005],tata[100005],mar[100005];
vector <int> v[100005];
void dfs(int x,int t,int nivel)
{
    int i;
    niv[x]=nivel;
    mar[x]=1;
    tata[x]=t;
    for (i=0;i<v[x].size();i++)
    {
        int nod=v[x][i];
        if (t!=nod)
        {
            dfs(nod,x,nivel+1);
            mar[x]+=mar[nod];
            if (mar[nod]>mar[max_fiu[x]])
            {
                max_fiu[x]=nod;
            }
        }
    }
}
int prim[100005],cnt[100005],q,poz[100005],id[100005];
void split(int x,int t)
{
    cnt[q]++;
    if (cnt[q]==1)
    {
        prim[q]=x;
    }
    id[x]=q;
    poz[x]=cnt[q];
    if (mar[x]==1)
    {
        return;
    }
    split(max_fiu[x],x);
    for (int i=0;i<v[x].size();i++)
    {
        int nod=v[x][i];
        if (nod!=t&&nod!=max_fiu[x])
        {
            q++;
            split(nod,x);
        }
    }
}
class SegmentTree
{
    int *arb;
public:
    inline void Initialize(int Elems)
    {
        arb= new int [((Elems<<4)+1)];
        for (int i=1;i<=(Elems<<2);i++)
        {
            arb[i]=0;
        }
        return ;
    }
    inline void update(int st,int dr,int nod,int poz,int val)
    {
        if (st==dr)
        {
            arb[nod]=val;
            return;
        }
        int mij=(st+dr)/2;
        if (poz<=mij)
        {
            update(st,mij,2*nod,poz,val);
        }
        else
        {
            update(mij+1,dr,2*nod+1,poz,val);
        }
        arb[nod]=max(arb[2*nod],arb[2*nod+1]);
    }
    inline int query(int st,int dr,int nod,int ua,int ub)
    {
        if (ua<=st&&dr<=ub)
        {
            return arb[nod];
        }
        int mij=(st+dr)/2;
        int r1=0,r2=0;
        if (ua<=mij)
        {
            r1=query(st,mij,2*nod,ua,ub);
        }
        if (mij<ub)
        {
            r2=query(mij+1,dr,2*nod+1,ua,ub);
        }
        return max(r1,r2);
    }
}*chains;
int query(int x,int y)
{
    if (id[x]==id[y])
    {
        int st,dr;
        st=min(poz[x],poz[y]);
        dr=max(poz[x],poz[y]);
        return chains[id[x]].query(1,cnt[id[x]],1,st,dr);
    }
    if (niv[prim[id[x]]]>niv[prim[id[y]]])
    {
        swap(x,y);
    }
    return max(query(y,prim[id[y]]),query(tata[prim[id[y]]],x));
}
int n,m,val[100005],i,x,y,tip;
int main()
{
    f>>n>>m;
    for (i=1;i<=n;i++)
    {
        f>>val[i];
    }
    for (i=1;i<n;i++)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1,0,1);
    q=1;
    split(1,0);
    chains = new SegmentTree [(q+1)];
    for (i=1;i<=q;i++)
    {
        chains[i].Initialize(cnt[i]);
    }
    for (i=1;i<=n;i++)
    {
        chains[id[i]].update(1,cnt[id[i]],1,poz[i],val[i]);
    }
    for (i=1;i<=m;i++)
    {
        f>>tip>>x>>y;
        if (tip==0)
        {
            chains[id[x]].update(1,cnt[id[x]],1,poz[x],y);
        }
        else
        {
            g<<query(x,y)<<'\n';
        }
    }
    return 0;
}