#include <fstream>
#include <vector>
#include <cstring>
#include <set>
#include <algorithm>
using namespace std;
ifstream fin ("heavypath.in");
ofstream fout("heavypath.out");
int i,n,m,x,y,k,t;
int V[100003],p[100003],pos[100003],heavy[100003],v[100003],A[400003],head[100003];
vector <int> L[100003];
int dfs(int nod,int t)
{
    p[nod]=t;
    int siz=1;
    int max_siz=0;
    for(auto j:L[nod])
        if(j!=t)
        {
            int siz_fiu;
            siz_fiu=dfs(j,nod);
            siz+=siz_fiu;
            if(siz_fiu>max_siz)
            {
                max_siz=siz_fiu;
                heavy[nod]=j;
            }
        }
    return siz;
}
void generate_paths(int nod,int hd,int t)
{
    head[nod]=hd;
    v[++k]=nod;
    pos[nod]=k;
    if(heavy[nod])
        generate_paths(heavy[nod],hd,nod);
    for(auto j:L[nod])
        if(j!=t&&j!=heavy[nod])
            generate_paths(j,j,nod);
}
void build(int nod,int st,int dr)
{
    if(st==dr)
        A[nod]=V[v[st]];
    else
    {
        int mid=(st+dr)/2;
        build(2*nod,st,mid);
        build(2*nod+1,mid+1,dr);
        A[nod]=max(A[2*nod],A[2*nod+1]);
    }
}
void update(int nod,int st,int dr,int poz,int val)
{
    if(st==dr)
        A[nod]=val;
    else
    {
        int mid=(st+dr)/2;
        if(poz<=mid)
            update(2*nod,st,mid,poz,val);
        else
            update(2*nod+1,mid+1,dr,poz,val);
        A[nod]=max(A[2*nod],A[2*nod+1]);
    }
}
int query(int nod,int st,int dr,int a,int b)
{
    if(a<=st&&dr<=b)
        return A[nod];
    int mid=(st+dr)/2;
    int val=0;
    if(a<=mid)
        val=max(val,query(2*nod,st,mid,a,b));
    if(mid+1<=b)
        val=max(val,query(2*nod+1,mid+1,dr,a,b));
    return val;
}
int path_query(int x,int y)
{
    int sol=0;
    while(head[x]!=head[y])
    {
        if(pos[head[x]]>pos[head[y]])
            swap(x,y);
        sol=max(sol,query(1,1,k,pos[head[y]],pos[y]));
        y=p[head[y]];
    }
    if(pos[x]>pos[y])
        swap(x,y);
    sol=max(sol,query(1,1,k,pos[x],pos[y]));
    return sol;
}
int main()
{
    fin>>n>>m;
    for(i=1;i<=n;i++)
        fin>>V[i];
    for(i=1;i<n;i++)
    {
        fin>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    dfs(1,0);
    generate_paths(1,1,0);
    build(1,1,k);
    for(i=1;i<=m;i++)
    {
        fin>>t;
        if(!t)
        {
            int nod,val;
            fin>>nod>>val;
            update(1,1,k,pos[nod],val);
        }
        else
        {
            fin>>x>>y;
            fout<<path_query(x,y)<<'\n';
        }
    }
    return 0;
}