#include <stdio.h>
#include <string.h>
#include <vector>
#define p push_back
#define  M 100005
using namespace std;int n,m,t,x,y,z,nrchain;int v[M],h[M],s[M],ind[M],poz[M],nodes[M],pLant[M],arb[2*M];vector<int>l[M],chain[M];bool viz[M];void dfs(int x,int p){int best=0;h[x]=h[p]+1;s[x]=1;for(int i=0;i<l[x].size();++i)if(l[x][i]!=p){dfs(l[x][i], x);s[x]+=s[l[x][i]];if(s[best]<s[l[x][i]])best=l[x][i];}for(int i=0;i<l[x].size();++i)if(l[x][i]!=p&&l[x][i]!=best)pLant[ind[l[x][i]]]=x;if(best==0)ind[x]=++nrchain;else ind[x]=ind[best];chain[ind[x]].p(x);}void buildArb(){for(int i=n;i>0;--i)arb[i]=max(arb[2*i],arb[2*i+1]);}void update(int pos,int val){pos+=n;arb[pos]=val;for(;pos>1;pos>>=1)arb[pos>>1]=max(arb[pos],arb[pos^1]);}int query(int x,int y){int res=0;x+=n;y+=n;while(x<y){if(x&1)res=max(res,arb[x++]);if(y&1)res=max(res,arb[--y]);x>>=1;y>>=1;}return res;}int hpd(int x,int y){int res=0;while(ind[x]!=ind[y]){if(h[pLant[ind[x]]]<h[pLant[ind[y]]])swap(x,y);res=max(res,query(poz[x],poz[chain[ind[x]].back()]+1));x=pLant[ind[x]];}if(poz[x]>poz[y])swap(x,y);return max(res,query(poz[x],poz[y]+1));}int main(){freopen("heavypath.in","r",stdin);freopen("heavypath.out","w",stdout);scanf("%d%d",&n,&m);for(int i=1;i<=n;++i)scanf("%d",&v[i]);for(int i=0;i<n-1;++i){scanf("%d%d",&x,&y);l[x].p(y);l[y].p(x);}dfs(1,0);int nr=0;for(int i=1;i<=nrchain;++i)for(int j=0;j<chain[i].size();++j){poz[chain[i][j]]=++nr;nodes[nr]=chain[i][j];arb[nr+n]=v[chain[i][j]];}buildArb();for(int i=0;i<m;i++){scanf("%d%d%d",&t,&x,&y);if(t==0)update(poz[x],y);if(t==1)printf("%d\n",hpd(x,y));}return 0;}