#include <fstream>
#include <vector>

using namespace std;

ifstream in("heavypath.in");
ofstream out("heavypath.out");

const int NMAX=1e5+5, LMAX=17;
int n, m, val[NMAX], p[NMAX], d[NMAX], hc[NMAX];
int dtlca, dthv, clc=1, pozlca[NMAX], pozhv[NMAX], lc[NMAX];
vector<int> adj[NMAX];

struct RMQ
{
    int rmq[LMAX+1][2*NMAX];
    
    void build()
    {
        for(int b=1;b<=LMAX;b++)
            for(int i=1;i+(1<<b)-1<=dtlca;i++)
                if(d[rmq[b-1][i]]<d[rmq[b-1][i+(1<<(b-1))]])
                    rmq[b][i]=rmq[b-1][i];
                else
                    rmq[b][i]=rmq[b-1][i+(1<<(b-1))];
    }
    
    int query(int l, int r)
    {
        if(l>r)
            swap(l, r);
        int lg=31-__builtin_clz(r-l+1);
        if(rmq[lg][l]<rmq[lg][r-(1<<lg)+1])
            return rmq[lg][l];
        return rmq[lg][r-(1<<lg)+1];
    }
}dslca;

struct AINT
{
    int aint[4*NMAX];
    
    void update(int nod, int l, int r, int poz, int val)
    {
        if(poz<l || r<poz)
            return;
        if(l==r)
        {
            aint[nod]=val;
            return;
        }
        int mid=(l+r)/2;
        update(2*nod, l, mid, poz, val);
        update(2*nod+1, mid+1, r, poz, val);
        aint[nod]=max(aint[2*nod], aint[2*nod+1]);
    }
    
    int query(int nod, int l, int r, int ql, int qr)
    {
        if(qr<l || r<ql)
            return 0;
        if(ql<=l && r<=qr)
            return aint[nod];
        int mid=(l+r)/2;
        return max(query(2*nod, l, mid, ql, qr),
                   query(2*nod+1, mid+1, r, ql, qr));
    }
}dshv;

int DFS(int u, int pu)
{
    int maxsz=0, szu=1;
    for(auto v:adj[u])
        if(v!=pu)
        {
            d[v]=d[u]+1; p[v]=u;
            int szv=DFS(v, u);
            szu+=szv;
            if(szv>maxsz)
            {
                maxsz=szv;
                hc[u]=v;
            }
        }
    return szu;
}

void DFSord(int u, int pu)
{
    dslca.rmq[0][++dtlca]=u;
    pozlca[u]=dtlca;
    
    dthv++; pozhv[u]=dthv; lc[u]=clc;
    dshv.update(1, 1, n, dthv, val[u]);
    
    if(hc[u]>0)
    {
        DFSord(hc[u], u);
        dslca.rmq[0][++dtlca]=u;
    }
    for(auto v:adj[u])
        if(v!=pu && v!=hc[u])
        {
            clc=v;
            DFSord(v, u);
            dslca.rmq[0][++dtlca]=u;
        }
}

int hvquery(int u, int su)
{
    int ans=0;
    while(d[su]<d[lc[u]])
    {
        ans=max(ans, dshv.query(1, 1, n, pozhv[lc[u]], pozhv[u]));
        u=p[lc[u]];
    }
    ans=max(ans, dshv.query(1, 1, n, pozhv[su], pozhv[u]));
    return ans;
}

int main()
{
    in>>n>>m;
    for(int i=1;i<=n;i++)
        in>>val[i];
    for(int i=1;i<n;i++)
    {
        int a, b; in>>a>>b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    
    DFS(1, 0);
    DFSord(1, 0);
    return 0;
    dslca.build();
    while(m--)
    {
        int t, x, y;
        in>>t>>x>>y;
        if(t==0)
            dshv.update(1, 1, n, pozhv[x], y);
        else
        {
            int lca=dslca.query(pozlca[x], pozlca[y]);
            out<<max(hvquery(x, lca), hvquery(y, lca))<<'\n';
        }
    }
    return 0;
}