Program Thanh_Noob;
Uses crt;
Var
        n: Integer;
        En: Real;
        gt, i: LongInt;
Begin
        clrscr; En:=1;
        gt:=1; i:=0;
        Repeat
                inc(i); gt:=gt*i;
                En:=En+(1/gt);
        Until (1/gt)<(2*1/1000000);
        Writeln('E(n)=',En:0:3);
        Readln;
End.