program  arbori_de_intervale;
var      f,g:text;
         bufin,bufout:array[1..1 shl 17] of char;
         n,m,i,x,poz,a,b,max:longint;
         arb:array of longint;
//----------------------------------
function maxim(a, b:longint):longint;
begin
        if a > b then maxim := a
                else maxim := b;
end;
//---------------------------------
procedure update(nod, st, dr:longint);
var     mij:longint;
begin
        if st = dr then arb[nod] := x
                else
           begin
              mij := (st + dr) div 2;
              if poz <= mij then update(2*nod, st, mij)
                            else update(2*nod + 1, mij + 1, dr);
              arb[nod] := maxim(arb[2*nod], arb[2*nod + 1]);
           end;
end;
//--------------------------------
procedure search(nod, st, dr:longint);
var     mij:longint;
begin
        if (a <= st) and (dr <= b) then
                begin
                  if max < arb[nod] then max := arb[nod];
                end
           else
                begin
                  mij := (st + dr) div 2;
                  if (a <= mij) then search(2*nod, st, mij);
                  if (mij < b) then search(2*nod+1, mij+1, dr);
                end;

end;
//---------------------------------
begin
        assign(f,'arbint.in'); reset(f);
        assign(g,'arbint.out'); rewrite(g);
        settextbuf(f, bufin); settextbuf(f, bufout);
        readln(f ,n, m);
        setlength(arb, n+m+1);
        for i := 1 to n do
                begin
                read(f, x); poz := i; update(1, 1, n);
                end;
        for i := 1 to m do
                begin
                  readln(f, x, a, b);
                  if x = 0 then
                        begin
                          max := 0; search(1,1,n); writeln(g,max);
                        end
                    else
                        begin
                          poz := a; x := b; update(1,1,n);
                        end;
                end;
        close(f); close(g);
end.