Program Happya;
Const
	inf = 'happya.in';
	ouf = 'happya.out';

Var
	a : array[0..400100,1..4] of longint;
	n,m,ans,i,x,y,c,tmp,tm : longint;
	ch : char;

Function Max(xx,yy : longint): longint;
	Begin
		if xx<yy then exit(yy);
		exit(xx);
	End;

Procedure Updata(left,right,root : longint);
	Var
		mid : longint;
	Begin
                a[root,4] := left;
                if (y<left) or (x>right) then exit;
		if (x<=left) and (y>=right) then
			begin
			  a[root,1] := a[root,1] + c;
			  a[root,2] := a[root,2] + c;
			  exit;
			end;

		mid := (left+right) div 2;
		inc(a[root*2,1],a[root,2]);
		inc(a[root*2,2],a[root,2]);
		inc(a[root*2+1,1],a[root,2]);
		inc(a[root*2+1,2],a[root,2]);
		a[root,2] := 0;

		Updata(left,mid,root*2);
		Updata(mid+1,right,root*2+1);

                if a[root*2,1]>=a[root*2+1,1]
                        then begin
                                a[root,1] := a[root*2,1];
	                        a[root,3] := a[root*2,3];
                                a[root,4] := a[root*2,4];
                             end
                        else begin
                                a[root,1] := a[root*2+1,1];
                                a[root,3] := a[root*2+1,3];
                                a[root,4] := a[root*2+1,4]
                             end;
        End;

Function Find(left,right,root : longint): longint;
	Var
		m1,m2,mid,tmp1,tmp2,tm1,tm2 : longint;
	Begin
		if (y<left)or(x>right) then exit(-maxlongint);
		if (x<=left)and(y>=right) then
                 begin tmp := a[root,3]; tm := a[root,4]; exit(a[root,1]); end;
                mid := (left+right) div 2;
                a[root*2,1]:=a[root*2,1]+a[root,2];
		a[root*2,2]:=a[root*2,2]+a[root,2];
		a[root*2+1,1]:=a[root*2+1,1]+a[root,2];
		a[root*2+1,2]:=a[root*2+1,2]+a[root,2];
		a[root,2]:=0;
		m1:=find(left,mid,root*2);
                tmp1 := tmp; tm1 := tm;
		m2:=find(mid+1,right,root*2+1);
                tmp2 := tmp; tm2 := tm;
                {if m1>=m2
                 then begin
                        a[root,1] := a[root*2,1];
                        a[root,3] := a[root*2,3];
                        a[root,4] := a[root*2,4];
                     end
                 else begin
                        a[root,1] := a[root*2+1,1];
                        a[root,3] := a[root*2+1,3];
                        a[root,4] := a[root*2+1,4];
                        end;}
                if m1>=m2 then begin tmp := tmp1; tm := tm1; end
                        else begin tmp := tmp2; tm := tm2; end;
		exit(Max(m1,m2));
	End;

Procedure Delete(x,left,right,root : longint);
        Var
                mid : longint;
        Begin
                if (left=right) then begin a[x,1] := 0; exit; end;
                mid := (left + right) div 2;
                if tm<=mid then Delete(x,left,mid,root*2)
                        else Delete(x,mid+1,right,root*2+1);
                if a[root*2,1]>=a[root*2+1,1]
                 then begin
                        a[root,1] := a[root*2,1];
                        a[root,3] := a[root*2,3];
                        a[root,4] := a[root*2,4];
                     end
                 else begin
                        a[root,1] := a[root*2+1,1];
                        a[root,3] := a[root*2+1,3];
                        a[root,4] := a[root*2+1,4];
                        end;
        End;


Begin
	Assign(input,inf); Reset(input);
	Assign(output,ouf); Rewrite(output);

	readln(n,m);
        for i := 1 to 2*n-1 do a[i,3] := i;
	for i := 1 to m do
		begin
		  read(ch);
		  if ch='I' then readln(x,y,c)
				else readln(x,y);
		  if ch='I' then Updata(1,n,1)
			else begin
				ans := Find(1,n,1);
                                a[tmp,1] := 0;
                                Delete(tmp,1,n,1);
				writeln(ans);
				end;
		end;

	Close(input); Close(output);
End.