#include <cstdio>
#include <vector>

using namespace std;

const int MaxN=100010;
vector<int> v[MaxN],arb[MaxN];
int val[MaxN],size[MaxN],niv[MaxN],lant[MaxN],lant_poz[MaxN],lant_size[MaxN],lant_tata[MaxN],nrlant;

void dfs1(int nod,int tata,int lev)
{
    size[nod]=1;
    niv[nod]=lev;
    for(vector<int>::iterator it=v[nod].begin();it!=v[nod].end();it++)
        if(*it!=tata)
        {
            dfs1(*it,nod,lev+1);
            size[nod]+=size[*it];
        }
}

void dfs2(int nod,int tata,int l)
{
    lant[nod]=l;
    lant_poz[nod]=++lant_size[l];
    int heavy=0;
    for(vector<int>::iterator it=v[nod].begin();it!=v[nod].end();it++)
        if(*it!=tata && size[*it]>size[heavy]) heavy=*it;
    if(!heavy) return;
    dfs2(heavy,nod,l);
    for(vector<int>::iterator it=v[nod].begin();it!=v[nod].end();it++)
        if(*it!=tata && *it!=heavy)
        {
            ++nrlant;
            lant_tata[nrlant]=nod;
            dfs2(*it,nod,nrlant);
        }
}

void arbint_update(int nod,int st,int dr,int poz,int val,vector<int> &arb)
{
    if(st==dr)
    {
        arb[nod]=val;
        return;
    }
    int mid=(st+dr)/2;
    if(poz<=mid) arbint_update(nod*2,st,mid,poz,val,arb);
    else arbint_update(nod*2+1,mid+1,dr,poz,val,arb);
    arb[nod]=max(arb[nod*2],arb[nod*2+1]);
}

int arbint_query(int nod,int st,int dr,int left,int right,vector<int> &arb)
{
    if(left<=st && dr<=right) return arb[nod];
    int mid=(st+dr)/2,sol=0;
    if(left<=mid) sol=max(sol,arbint_query(nod*2,st,mid,left,right,arb));
    if(mid<right) sol=max(sol,arbint_query(nod*2+1,mid+1,dr,left,right,arb));
    return sol;
}

int main()
{
    freopen("heavypath.in", "r", stdin);
    freopen("heavypath.out", "w", stdout);
    int n,m,x,y,tip;
    scanf("%d%d",&n,&m);
    for(int i=1;i<=n;i++) scanf("%d",&val[i]);
    for(int i=1;i<n;i++)
    {
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs1(1,0,1);
    nrlant++;
    dfs2(1,0,nrlant);
    for(int i=1;i<=nrlant;i++) arb[i].resize(lant_size[i]*4);
    for(int i=1;i<=n;i++) arbint_update(1,1,lant_size[lant[i]],lant_poz[i],val[i],arb[lant[i]]);
    for(int i=1;i<=m;i++)
    {
        scanf("%d%d%d",&tip,&x,&y);
        if(tip==0) arbint_update(1,1,lant_size[lant[x]],lant_poz[x],y,arb[lant[x]]);
        else
        {
            int sol=0;
            while(lant[x]!=lant[y])
            {
                if(niv[lant_tata[lant[x]]]<niv[lant_tata[lant[y]]]) swap(x,y);
                sol=max(sol,arbint_query(1,1,lant_size[lant[x]],1,lant_poz[x],arb[lant[x]]));
                x=lant_tata[lant[x]];
            }
            if(lant_poz[x]>lant_poz[y]) swap(x,y);
            sol=max(sol,arbint_query(1,1,lant_size[lant[x]],lant_poz[x],lant_poz[y],arb[lant[x]]));
            printf("%d\n",sol);
        }
    }
    return 0;
}