Program FNG;
Uses crt;
Var n,i: longint;
s: extended;
Function giaithua(a: longint): qword;
Var i: longint;
Begin
giaithua:=1;
For i:=1 to a do
giaithua:=giaithua*i;
End;
Begin
Clrscr;
Write('Nhap n: '); Readln(n);
s:=0;
For i:=1 to n do
s:=s+1/giaithua(i);
Write('S = ',s:0:2);
Readln
End.