uses crt;
var
  tin,tout:text;
  aa,bb:longint;
begin
  assign(tin,'DATA1.txt');reset(tin);
  assign(tout,'OUT1.txt');rewrite(tout);
  readln(tin,x);
  x:=x / 0.70;
  x:=x / 0.99;
  writeln(tout,x);
  close(tout);
end.