#include <stdio.h>
#include <vector>
#include <algorithm>
#define NMax 100010
using namespace std;
 
const char IN[]="heavypath.in",OUT[]="heavypath.out";
 
int N,M,L,Lanturi;
int v[NMax],nv[NMax],lant[NMax],nivel[NMax],primulDinLant[NMax],parinteLant[NMax],pozParc[NMax],parcurgere[NMax],T[NMax];
int arb[4*NMax];
vector<int> ad[NMax];
 
void dfs(int x,int p=0){
    int i;
    T[x]=1;nivel[x]=nivel[p]+1;
    for (i=0;i<(int)ad[x].size();++i) if (ad[x][i]!=p)
        dfs(ad[x][i],x),
        T[x]+=T[ad[x][i]];
}
 
void makeHeavy(int x,int p=0){
 
    int i,m=0,next=0;
 
    pozParc[x]=++L;
    parcurgere[L]=x;
    lant[x]=Lanturi;
 
    for (i=0;i<(int)ad[x].size();++i) if (ad[x][i]!=p && T[ad[x][i]]>m)
        m=T[ad[x][i]],next=ad[x][i];
 
    if (!next) return;
 
    makeHeavy(next,x);
 
    for (i=0;i<(int)ad[x].size();++i) if (ad[x][i]!=p && ad[x][i]!=next){
        ++Lanturi;
        parinteLant[Lanturi]=x;
        primulDinLant[Lanturi]=L+1;
        makeHeavy(ad[x][i],x);
    }
}
 
void update(int poz,int st,int dr,int x,int val){
 
    if (st==dr){
        arb[poz]=val;
        return;
    }
    int m=(st+dr)>>1;
    if (x<=m) update(2*poz,st,m,x,val);
    else      update(2*poz+1,m+1,dr,x,val);
    arb[poz]=max(arb[2*poz],arb[2*poz+1]);
}
 
int query(int poz,int st,int dr,int x,int y){
 
    if (x<=st && dr<=y)
        return arb[poz];
    int m=(st+dr)>>1,ret=-1;
 
    if (x<=m) ret=max(ret,query(2*poz,st,m,x,y));
    if (y >m) ret=max(ret,query(2*poz+1,m+1,dr,x,y));
 
    return ret;
}
 
void make(int poz,int st,int dr){
 
    if (st==dr){
        arb[poz]=nv[st];
        return;
    }
    int m=(st+dr)>>1;
    make(2*poz,st,m);
    make(2*poz+1,m+1,dr);
    arb[poz]=max(arb[2*poz],arb[2*poz+1]);
}
 
int get(int x,int y){
 
    int ret=-1;
 
    while (lant[x]!=lant[y]){
 
        if (nivel[parinteLant[lant[x]]]>nivel[parinteLant[lant[y]]]){
            ret=max(ret,query(1,1,N,primulDinLant[lant[x]],pozParc[x]));
            x=parinteLant[lant[x]];
        }else{
            ret=max(ret,query(1,1,N,primulDinLant[lant[y]],pozParc[y]));
            y=parinteLant[lant[y]];
        }
    }
 
    if (pozParc[x]>pozParc[y]) swap(x,y);
    ret=max(ret,query(1,1,N,pozParc[x],pozParc[y]));
    return ret;
}
 
int main()
{
    int i,t,x,y;
    freopen(IN,"r",stdin);
    scanf("%d%d",&N,&M);
    for (i=1;i<=N;++i) scanf("%d",v+i);
    for (i=1;i<N;++i)
    {
        scanf("%d%d",&x,&y);
        ad[x].push_back(y);
        ad[y].push_back(x);
    }
 
    dfs(1);
    ++Lanturi;
    makeHeavy(1);
    for (i=1;i<=N;++i) nv[pozParc[i]]=v[i];
    make(1,1,N);
 
    freopen(OUT,"w",stdout);
    while (M--){
 
        scanf("%d%d%d",&t,&x,&y);
        if (t==0){ //UPDATE
            update(1,1,N,pozParc[x],y);
            nv[pozParc[x]]=y;
        }
        else{ //QUERY
            printf("%d\n",get(x,y));
        }
    }
    fclose(stdout);
 
    return 0;
}