/**
 * Grains
 */
public class Grains {

  public static void main(String[] args) {

    System.out.println(grainsCount());
  }

  public static double grainsCount() {
    // Calculate the number of grains of wheat on a chessboard given that the number
    // on each square doubles.
    double gCount = 0;
    double grainOnCurrentSQ = 1;
    for (int i = 1; i <= 64; i++) {
      gCount += grainOnCurrentSQ;
      grainOnCurrentSQ *= 2;
    }
    return gCount;
  }
}