#include <fstream>
#include <vector>

using namespace std;
ifstream cin("heavypath.in");
ofstream cout("heavypath.out");
int n,q,A[100005];
int idx,G[200005],top[100005],nxt[200005];
int sz[100005],fa[100005],head[100005],lvl[100005],hv_son[100005],pos[100005],tmp;
int aint[200005];
void add_edge(int x,int y)
{
    idx++;
    G[idx]=y;
    nxt[idx]=top[x];
    top[x]=idx;
}
void build()
{
    for(int i=0;i<n;i++)
        aint[n+i]=A[pos[i+1]];
    for(int i=n-1;i>=1;i--)
        aint[i]=max(aint[2*i],aint[2*i+1]);
}
void update(int x,int v)
{
    x+=n-1;
    aint[x]=v;
    for(x>>=1;x;x>>=1)
        aint[x]=max(aint[2*x],aint[2*x+1]);
}
int query(int l,int r)
{
    int ans=0;
    for(l+=n-1,r+=n;l<r;l>>=1,r>>=1)
    {
        if(l&1) ans=max(ans,aint[l++]);
        if(r&1) ans=max(ans,aint[--r]);
    }
    return ans;
}
void dfs(int x,int tata)
{
    int sz_max=0;
    fa[x]=tata;
    sz[x]=1;
    lvl[x]=lvl[tata]+1;
    for(int i=top[x];i;i=nxt[i])
    {
        int y=G[i];
        if(y==tata)
            continue;
        dfs(y,x);
        sz[x]+=sz[y];
        if(sz[y]>sz_max)
        {
            sz_max=sz[y];
            hv_son[x]=y;
        }
    }
}
void decompose(int x,int hd)
{
    head[x]=hd;
    pos[x]=++tmp;
    if(hv_son[x])
        decompose(hv_son[x],hd);
    for(int i=top[x];i;i=nxt[i])
    {
        int y=G[i];
        if(y==fa[x] || y==hv_son[x])
            continue;
        decompose(y,y);
    }
}
int solve(int x,int y)
{
    int ans=0;
    while(head[x]!=head[y])
    {
        if(lvl[head[x]]<lvl[head[y]])
            swap(x,y);
        ans=max(ans,query(pos[head[x]],pos[x]));
        x=fa[head[x]];
    }
    if(pos[x]>pos[y])
        swap(x,y);
    ans=max(ans,query(pos[x],pos[y]));
    return ans;
}
int main()
{
    cin>>n>>q;
    for(int i=1;i<=n;i++)
        cin>>A[i];
    for(int i=1;i<=n-1;i++)
    {
        int x,y;
        cin>>x>>y;
        add_edge(x,y);
        add_edge(y,x);
    }
    dfs(1,0);
    decompose(1,1);
    build();
    int op,x,y;
    while(q--)
    {
        cin>>op>>x>>y;
        if(op==0)
            update(pos[x],y);
        if(op==1)
            cout<<solve(x,y)<<"\n";
    }
    return 0;
}