#include<stdio.h>
#include<iostream>
#include<vector>
#include<algorithm>
#define pb push_back
using namespace std;
int N,M,q,x,y,K;
int poz[1000100],v[100100],nr[100100],l[100100],p[100100],cmp[100100];
bool viz[100100];
vector<vector<int> > t;
vector<int> g[100100], c[100100];

void update(int comp, int nod, int st, int dr, int c, int d) {
    if(st==dr) {
        t[comp][nod]=d;
        return;
    }
    int mij = (st+dr)/2;
    if(c<=mij) {
        update(comp,2*nod,st,mij,c,d);
    } else {
        update(comp,2*nod+1,mij+1,dr,c,d);
    }
    t[comp][nod] = max(t[comp][2*nod],t[comp][2*nod+1]);
}
  
int getmax(int comp, int nod, int st, int dr, int c, int d) {
    int ret = 0; 
    if(c<=st && dr<=d) {
        return t[comp][nod];
    }
    int mij = (st+dr)/2;
    if(d>mij) {
        ret = max(ret,getmax(comp,nod*2+1,1+mij,dr,c,d));
    } 
    if(c<=mij) {
        ret = max(ret,getmax(comp,nod*2,st,mij,c,d));
    }
    return ret;
}

void update_val(int comp, int poz, int val) {
    update(comp, 1, 1, c[comp].size(), poz+1, val);
    v[c[comp][poz]] = val;
}

int query_val(int comp, int st, int dr) {
    return getmax(comp, 1, 1, c[comp].size(), st+1, dr+1); 
}

int find_max(int x, int y) {
    if(cmp[x] == cmp[y]) {
        return query_val(cmp[x],min(poz[x],poz[y]),max(poz[x],poz[y]));
    }
    int px = p[c[cmp[x]][0]];
    int py = p[c[cmp[y]][0]];
    if(l[px] < l[py]) {
        swap(x,y);
        swap(px,py);
    }
    int M = query_val(cmp[x],0,poz[x]);
    return max(M, find_max(px,y));
}

void dfs(int x) {
    viz[x] = 1;
    nr[x] = 1;
    int ind = -1, nrc = -1;
    for(auto y: g[x]) {
        if(viz[y]) continue;
        l[y] = l[x] + 1;
        p[y] = x;
        dfs(y);
        if(nr[y] > nrc) {
            ind = y;
            nrc = nr[y];
        }
        nr[x] += nr[y];
    }
    if(nrc == -1) {
        vector<int> C;
        C.pb(x);
        ++K;
        c[K] = C;
        cmp[x] = K;
    } else {
        c[cmp[ind]].pb(x);
        cmp[x] = cmp[ind];
    }
}

int main() {
	freopen("heavypath.in","r",stdin);
	freopen("heavypath.out","w",stdout);
	//freopen("input.in","r",stdin);
	scanf("%d%d",&N,&M);
    for(int i=1;i<=N;++i) {
        scanf("%d",&v[i]);
    }
    for(int i=1;i<N;++i) {
        scanf("%d%d",&x,&y);
        g[x].pb(y);
        g[y].pb(x);
    }
    l[1] = 1;
    dfs(1);
    for(int i=1;i<=K;++i) {
        reverse(c[i].begin(),c[i].end());
        for(int j=0;j<c[i].size();++j) {
            poz[c[i][j]] = j;
        }
    }
    t.resize(K+10);
    for(int i=1;i<=K;++i) {
        t[i].resize(4*c[i].size()+10,0);
    }
    for(int i=1;i<=N;++i) {
        update_val(cmp[i],poz[i],v[i]);
    }
    for(int i=1;i<=M;++i) {
        scanf("%d%d%d",&q,&x,&y);
        if(q==0) {
            update_val(cmp[x],poz[x],y);
        } else {
            printf("%d\n",find_max(x,y));
        }
    }
    return 0;
}