Write a recursive function in **Python** which takes one integer as function argument and checks whether the number is **Armstrong Number** or not.

**Definition**: An **Armstrong Number** is any number of N digits which is equal to the sum of N^{th} power of digits in the number.

Generally in most programming cases, we consider numbers from 0 to 999, i.e. 3-digit numbers. Thus, we also define an Armstrong number as any number of three digits as the sum of the cubes of digits in a given number.

**Example**:

3-digit Armstrong Number = 153 because 1^{3} + 5^{3} + 3^{3} = 153.

4-digit Armstrong Number = 1634 because 1^{4} + 6^{4} + 3^{4} + 4^{4} = 1634.

```
num = int(input("Enter the number: "))
size = len(str(num))
sum = 0
def isArmstrong(n):
global sum
global num
global size
if n < 10:
sum += n ** size
return num == sum
else:
sum += (n % 10) ** size
return isArmstrong(n // 10)
if isArmstrong(num):
print(str(num) + " is an Armstrong Number.")
else:
print(str(num) + " is NOT an Armstrong Number.")
```