Program arbint;
 var arb:array [1..410000] of longint;
     i,n,m,op,a,b,pos,val,max1:longint;
     b1,b2:array [1..1 shl 17] of char;
     fi,fo:text;
function max(a,b:longint):longint;
 begin
  if a>b then max:=a else max:=b;
 end;
procedure update(nod,l,r:longint);
var mid:longint;
 begin
  if l=r then begin arb[nod]:=val; exit; end;
  mid:=(l+r) div 2;
  if pos<=mid then update(2*nod,l,mid)
                  else update(2*nod+1,mid+1,r);
    arb[nod]:=max(arb[2*nod],arb[2*nod+1]);
  end;
procedure query(nod,l,r:longint);
 var mid:longint;
begin
 if (pos<=l) and (r<=val) then begin max1:=max(max1,arb[nod]); exit; end;
  mid:=(l+r) div 2;
   if pos<=mid then query(2*nod,l,mid);
    if mid<val then query(2*nod+1,mid+1,r);
end;
begin
 assign(fi,'arbint.in');
  assign(fo,'arbint.out');
 settextbuf(fi,b1); settextbuf(fo,b2);
 reset(fi); rewrite(fo); readln(fi,n,m);
  for i:=1 to n do begin
                    read(fi,op); pos:=i; val:=op;
                     update(1,1,n);
                    end;  readln(fi);
  for i:=1 to m do begin
                    readln(fi,op,a,b);
                    if op=0 then begin max1:=-1; pos:=a; val:=b; query(1,1,n); writeln(fo,max1); end
                            else begin pos:=a; val:=b; update(1,1,n); end;
                    end;
  close(fo);
end.