var
Mas: array of real;
Count, i: Cardinal;
Prois: real;
begin
// ввод
Write('Длина массива?');
Readln(Count);
Setlength(Mas, Count);
For i := 0 to Count - 1 do
begin
Readln(Mas[i]);
end;
// Решение
Prois := 1;
For i := 0 to Count - 1 do
begin
if Mas[i] < 0 then
Prois := Prois * Mas[i];
end;
if Prois >= 0 then
Writeln(sqrt(Prois))
else
Writeln(sqrt(-Prois), '*i');
end.