#include <fstream>
#include <vector>
#include <cstring>
#include <set>
#include <algorithm>
using namespace std;
class InParser {
private:
	FILE *fin;
	char *buff;
	int sp;

	char read_ch() {
		++sp;
		if (sp == 4096) {
			sp = 0;
			fread(buff, 1, 4096, fin);
		}
		return buff[sp];
	}

public:
	InParser(const char* nume) {
		fin = fopen(nume, "r");
		buff = new char[4096]();
		sp = 4095;
	}

	InParser& operator >> (int &n) {
		char c;
		while (!isdigit(c = read_ch()) && c != '-');
		int sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}

	InParser& operator >> (long long &n) {
		char c;
		n = 0;
		while (!isdigit(c = read_ch()) && c != '-');
		long long sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}
};
class OutParser {
private:
    FILE *fout;
    char *buff;
    int sp;

    void write_ch(char ch) {
        if (sp == 50000) {
            fwrite(buff, 1, 50000, fout);
            sp = 0;
            buff[sp++] = ch;
        } else {
            buff[sp++] = ch;
        }
    }


public:
    OutParser(const char* name) {
        fout = fopen(name, "w");
        buff = new char[50000]();
        sp = 0;
    }
    ~OutParser() {
        fwrite(buff, 1, sp, fout);
        fclose(fout);
    }

    OutParser& operator << (int vu32) {
        if (vu32 <= 9) {
            write_ch(vu32 + '0');
        } else {
            (*this) << (vu32 / 10);
            write_ch(vu32 % 10 + '0');
        }
        return *this;
    }

    OutParser& operator << (long long vu64) {
        if (vu64 <= 9) {
            write_ch(vu64 + '0');
        } else {
            (*this) << (vu64 / 10);
            write_ch(vu64 % 10 + '0');
        }
        return *this;
    }

    OutParser& operator << (char ch) {
        write_ch(ch);
        return *this;
    }
    OutParser& operator << (const char *ch) {
        while (*ch) {
            write_ch(*ch);
            ++ch;
        }
        return *this;
    }
};
InParser fin ("heavypath.in");
OutParser fout("heavypath.out");
int i,n,m,x,y,k,t;
int niv[100003],V[100003],p[100003],pos[100003],heavy[100003],v[100003],A[400003],head[100003];
vector <int> L[100003];
int dfs(int nod,int t)
{
    niv[nod]=niv[t]+1;
    p[nod]=t;
    int siz=1;
    int max_siz=0;
    for(auto j:L[nod])
        if(j!=t)
        {
            int siz_fiu;
            siz_fiu=dfs(j,nod);
            siz+=siz_fiu;
            if(siz_fiu>max_siz)
            {
                max_siz=siz_fiu;
                heavy[nod]=j;
            }
        }
    return siz;
}
void generate_paths(int nod,int hd,int t)
{
    head[nod]=hd;
    v[++k]=nod;
    pos[nod]=k;
    if(heavy[nod])
        generate_paths(heavy[nod],hd,nod);
    for(auto j:L[nod])
        if(j!=t&&j!=heavy[nod])
            generate_paths(j,j,nod);
}
void build(int nod,int st,int dr)
{
    if(st==dr)
        A[nod]=V[v[st]];
    else
    {
        int mid=(st+dr)/2;
        build(2*nod,st,mid);
        build(2*nod+1,mid+1,dr);
        A[nod]=max(A[2*nod],A[2*nod+1]);
    }
}
void update(int nod,int st,int dr,int poz,int val)
{
    if(st==dr)
        A[nod]=val;
    else
    {
        int mid=(st+dr)/2;
        if(poz<=mid)
            update(2*nod,st,mid,poz,val);
        else
            update(2*nod+1,mid+1,dr,poz,val);
        A[nod]=max(A[2*nod],A[2*nod+1]);
    }
}
int query(int nod,int st,int dr,int a,int b)
{
    if(a<=st&&dr<=b)
        return A[nod];
    int mid=(st+dr)/2;
    int val=0;
    if(a<=mid)
        val=max(val,query(2*nod,st,mid,a,b));
    if(mid+1<=b)
        val=max(val,query(2*nod+1,mid+1,dr,a,b));
    return val;
}
int path_query(int x,int y)
{
    int sol=0;
    while(head[x]!=head[y])
    {
        if(niv[head[x]]>niv[head[y]])
            swap(x,y);
        sol=max(sol,query(1,1,k,pos[head[y]],pos[y]));
        y=p[head[y]];
    }
    if(niv[x]>niv[y])
        swap(x,y);
    sol=max(sol,query(1,1,k,pos[x],pos[y]));
    return sol;
}
int main()
{
    fin>>n>>m;
    for(i=1;i<=n;i++)
        fin>>V[i];
    for(i=1;i<n;i++)
    {
        fin>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    dfs(1,0);
    generate_paths(1,1,0);
    build(1,1,k);
    for(i=1;i<=m;i++)
    {
        fin>>t;
        if(!t)
        {
            int nod,val;
            fin>>nod>>val;
            update(1,1,k,pos[nod],val);
        }
        else
        {
            fin>>x>>y;
            fout<<path_query(x,y)<<'\n';
        }
    }
    return 0;
}