var
a, b, c, d : real;
begin
read (a, b, c, d);
if a < 0 then writeln (a);
if b < 0 then writeln (b);
if c < 0 then writeln (c);
if d < 0 then writeln (d);
end.
var
a, b, c, d : real;
begin
read (a, b, c, d);
if a < 0 then writeln (a);
if b < 0 then writeln (b);
if c < 0 then writeln (c);
if d < 0 then writeln (d);
end.