#include <bits/stdc++.h>

using namespace std;

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

int niv[100001],w[100001],v[100001],aint[400004],head[100001],nou[100001],poz[100001],tata[100001],k,n,m;
vector <int> a[100001];

void dfs(int x)
{   w[x]=1;
    for (auto y:a[x])
    if (y!=tata[x])
    {
        tata[y]=x;
        niv[y]=niv[x]+1;
        dfs(y);
        w[x]+=w[y];
    }
}

void dfs_heavy(int x)
{
    int heavy=0;
    nou[++k]=x;
    poz[x]=k;
    for (auto y:a[x])
    if (y!=tata[x] && w[y]>w[heavy])
        heavy=y;
    if (heavy!=0)
    {
        head[heavy]=head[x];
        dfs_heavy(heavy);
        for (auto y:a[x])
        if (y!=tata[x] && y!=heavy)
            dfs_heavy(y);
    }
}

void updater(int nod, int st, int dr, int poz, int val)
{
    if (st==dr)
        aint[nod]=val;
    else
    {
        int mij=(st+dr)/2;
        if (poz<=mij)
            updater(2*nod,st,mij,poz,val);
        else
            updater(2*nod+1,mij+1,dr,poz,val);
        aint[nod]=max(aint[2*nod],aint[2*nod+1]);
    }
}

void update(int poz, int val)
{
    updater(1,1,n,poz,val);
}

void update_heavy(int x, int y)
{
    update(poz[x],y);
}

int querysolver(int nod, int st, int dr, int left, int right)
{
    if (st==left && dr==right)
        return aint[nod];
    else
    {
        int mij=(st+dr)/2;
        if (right<=mij)
            return querysolver(2*nod,st,mij,left,right);
        if (left>mij)
            return querysolver(2*nod+1,mij+1,dr,left,right);
        else
            return max(querysolver(2*nod,st,mij,left,mij),querysolver(2*nod+1,mij+1,dr,mij+1,right));
    }
}

int query(int st, int dr)
{
    return querysolver(1,1,n,st,dr);
}

int query_heavy(int x, int y)
{
    int sol;
    if (head[x]==head[y])
    {
        if (niv[x]>niv[y])
            swap(x,y);
        sol=query(poz[x],poz[y]);
    }
    else
    {
        if (niv[head[x]]<niv[head[y]])
            swap(x,y);
        sol=query(poz[head[x]],poz[x]);
        x=tata[head[x]];
        sol=max(sol,query_heavy(x,y));
    }
    return sol;
}

int main()
{   int i,x,y,c;
    f>>n>>m;
    for (i=1;i<=n;i++)
        f>>v[i];
    for (i=1;i<n;i++)
    {
        f>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1);
    for (i=1;i<=n;i++)
        head[i]=i;
    dfs_heavy(1);
    for (i=1;i<=n;i++)
        update_heavy(i,v[i]);
    for (i=1;i<=m;i++)
    {
        f>>c>>x>>y;
        if (c==0)
            update_heavy(x,y);
        else
            g<<query_heavy(x,y)<<'\n';
    }

}