var a:array [1..13] of real; i: integer; q,s:real;begin s:=3; a[1]:=3; a[2]:=6; a[3]:=12; a[4]:=24; q:=a[2]/a[1]; for i:=2 to 13 do begin a[i]:=a[i-1]*q; s:=s+a[i]; end; writeln(s);end.
var a:array [1..13] of real;
i: integer;
q,s:real;
begin
s:=3;
a[1]:=3;
a[2]:=6;
a[3]:=12;
a[4]:=24;
q:=a[2]/a[1];
for i:=2 to 13 do
begin
a[i]:=a[i-1]*q;
s:=s+a[i];
end;
writeln(s);
end.