Program hotrotinhoc;
var n,x,i: integer;
s: real;
function t1(d: integer): longint;
var i,t: longint;
begin
t:=1;
for i:=1 to d do t:=t*i;
t1:=t;
end;
function t2(a,b: integer): longint;
var i,tg: integer;
begin
tg:=1;
for i:=1 to a do tg:=tg*b;
t2:=tg;
end;
begin
write('n='); readln(n);
write('x='); readln(x);
s:=1;
for i:=1 to n do
if i mod 2=1 then s:=s-((t2(i,x))/(t1(i))) else s:=s+((t2(i,x))/(t1(i)));
write(s:1:2);
readln
end.