input: Write a function to find the GCD of two numbers using the Euclidean algorithm.
  
  def findGCD(a, b): 
     if (b == 0): 
         return a
     return findGCD(b, a % b)
  
  assert findGCD(1000, 500) == 500
  assert findGCD(36, 48) == 12
  assert findGCD(270, 192) == 6
  assert findGCD(77, 33) == 11
  assert findGCD(1, 1) == 1
output: def findGCD(a, b): 
     if (b == 0): 
         return a
     return findGCD(b, a % b)