output_description: Output the greatest common divisor of _a_ and _b_.
input_description: _a_ and _b_ are given in a line sparated by a single space.
attempt: # Euclidean Algorithm
  x, y = map(int, input().split(" "))
  q = x % y
  while q != 0:
      t = y
      y = q
      x = t
      q = x % y
  print(y)
  
problem_description: Greatest Common Divisor
  
  Write a program which finds the greatest common divisor of two natural numbers
  _a_ and _b_
samples: [{"input": "54 20", "output": "2"}, {"input": "147 105", "output": "21"}]