#include <bits/stdc++.h>
#define SIZE 100005
using namespace std;

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

int n,m,k,aint[4*SIZE],val[SIZE],tata[SIZE],sz[SIZE],niv[SIZE],head[SIZE],v[SIZE],poz[SIZE];
vector<int>a[SIZE];

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

void update(int index,int newvalue)
{
    update(1,1,n,index,newvalue);
}

int query(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 query(2*nod,st,mij,left,right);
        else if(left>mij)return query(2*nod+1,mij+1,dr,left,right);
        else return max(query(2*nod,st,mij,left,mij),query(2*nod+1,mij+1,dr,mij+1,right));
    }
}

int query(int left,int right)
{
    return query(1,1,n,left,right);
}

void dfs(int nod)
{
    sz[nod]=1;
    for(auto u:a[nod])
        if(u!=tata[nod])
    {
        niv[u]=niv[nod]+1;
        tata[u]=nod;
        dfs(u);
        sz[nod]+=sz[u];
    }
}

void dfs_greu(int nod)
{
    int heavy=0;
    v[++k]=nod;
    poz[nod]=k;
    for(auto u:a[nod])
        if(u!=tata[nod] && sz[u]>sz[heavy])heavy=u;
    if(!heavy)return;
    head[heavy]=head[nod];
    dfs_greu(heavy);
    for(auto u:a[nod])
        if(u!=heavy && u!=tata[nod])dfs_greu(u);
}

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

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,t;
    f>>n>>m;
    for(i=1;i<=n;i++)f>>val[i];
    for(i=1;i<=n-1;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_greu(1);
    for(i=1;i<=n;i++)update_heavy(i,val[i]);
    for(i=1;i<=m;i++)
    {
        f>>t>>x>>y;
        if(t==0)
        {
            update_heavy(x,y);
        }
        else
        {
            g<<query_heavy(x,y)<<'\n';
        }
    }
    return 0;
}