uses crt, math;
var k,i,f1,f2,f3:integer;
x,s1,s2,f:real;
function fact (k:integer):integer;
begin
f1:=(k+2);
f2:=1;
for i:=1 to f1 do
f2:=f2*i;
f3:=f2;
end;
begin
clrscr;
write('x=');
read (x);
k:=0;
fact(k);
s1:=sqr(x)/f3;
k:=1;
fact(k);
s2:=-1* power(x,3)/2*f3;
k:=2;
while (s2-s1)>power(10,-6) do begin
fact(k);
if s1>s2 then
s1:=s2+(power(-1,k)*power(x,(k+2))/(k+1)*f3)
else
s2:=s1+(power(-1,k)*power(x,(k+2))/(k+1)*f3);
k:=k+1;
end;
write(s2:5:10);
readkey;
end.