uses crt;
var x,n,i:longint; s:real;
function giaithua(a:longint):longint;
var i:longint;
begin
giaithua:=1;
for i:=1 to a do giaithua:=giaithua*i;
end;
begin
clrscr;
s:=1;
write('x=');readln(x);
write('n=');readln(n);
for i:=1 to n do s:=s+x*i/giaithua(i);
writeln(s:0:2);
readln
end.