input: Write a function to find the GCD of two numbers using the Euclidean algorithm. The function should take two integers as input and return their greatest common divisor. If the second number is 0, return the first number as the GCD.
  assert findGCD(1000, 500) == 500
  assert findGCD(35, 15) == 5
  assert findGCD(10, 0) == 10
  assert findGCD(0, 5) == 5
  assert findGCD(23, 11) == 1
  
  def findGCD(a, b): 
     if (b == 0): 
         return a
     return findGCD(b, a % b)
output: def findGCD(a, b): 
     if (b == 0): 
         return a
     return findGCD(b, a % b)