var
x,y,z: real;
sign: char;
begin
while True do begin
write('sign: '); readln(sign);
if sign = '0' then break;
if sign in ['+','-','*','/'] then begin
write('x='); readln(x);
write('y='); readln(y);
case sign of
'+': begin z := x + y; writeln(z:5:2) end;
'-': begin z := x - y; writeln(z:5:2); end;
'*': begin z := x * y; writeln(z:5:2); end;
'/': if y <> 0 then begin
z := x / y;
writeln(z:5:2)
end
else
writeln('Division by zero!');
end;
end
else writeln('Bad sign!')
end;
end.