def calculate_total_grains():
    total_grains = 0
    grains_on_current_square = 1

    for square in range(1, 65):
        total_grains += grains_on_current_square
        grains_on_current_square *= 2

    return total_grains

if __name__ == "__main__":
    total_grains = calculate_total_grains()
    print(f"Celkový počet zrnek na šachovnici je: {total_grains}")