Rewrite the following code in an object-oriented style.
def calculate_area(length, width):
  return length * width
class Rectangle:
    
    def __init__(self, length, width):
        self.length = length
        self.width = width
        
    def calculate_area(self):
        return self.length * self.width

R=Rectangle(5, 4) 
print(R.calculate_area()) #20
Complete the following task based on the instruction and optional input provided.### Instruction:
Rewrite the following code in an object-oriented style.

### Input:
def calculate_area(length, width):
  return length * width

### Output:
class Rectangle:
    
    def __init__(self, length, width):
        self.length = length
        self.width = width
        
    def calculate_area(self):
        return self.length * self.width

R=Rectangle(5, 4) 
print(R.calculate_area()) #20