output_description: Print an integer representing the number of points such that the distance from
  the origin is at most D.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N D
      X_1 Y_1
      \vdots
      X_N Y_N
attempt: z = [map(int, t.split()) for t in open(0)]
  print(sum(x * x + y * y <= z[0][1] ** 2 for x, y in z))
  
problem_description: Statement
  
  We have N points in the two-dimensional plane. The coordinates of the i-th
  point are (X_i,Y_i).
  
  Among them, we are looking for the points such that the distance from the
  origin is at most D. How many such points are there?
  
  We remind you that the distance between the origin and the point (p, q) can be
  represented as \sqrt{p^2+q^2}.
samples: [{"input": "4 5\n    0 5\n    -2 4\n    3 4\n    4 -4", "output": "3\n    \n\nThe distance between the origin and each of the given points is as follows:\n\n  * \\sqrt{0^2+5^2}=5\n  * \\sqrt{(-2)^2+4^2}=4.472\\ldots\n  * \\sqrt{3^2+4^2}=5\n  * \\sqrt{4^2+(-4)^2}=5.656\\ldots\n\nThus, we have three points such that the distance from the origin is at most\n5.\n\n* * *"}, {"input": "12 3\n    1 1\n    1 1\n    1 1\n    1 1\n    1 2\n    1 3\n    2 1\n    2 2\n    2 3\n    3 1\n    3 2\n    3 3", "output": "7\n    \n\nMultiple points may exist at the same coordinates.\n\n* * *"}, {"input": "20 100000\n    14309 -32939\n    -56855 100340\n    151364 25430\n    103789 -113141\n    147404 -136977\n    -37006 -30929\n    188810 -49557\n    13419 70401\n    -88280 165170\n    -196399 137941\n    -176527 -61904\n    46659 115261\n    -153551 114185\n    98784 -6820\n    94111 -86268\n    -30401 61477\n    -55056 7872\n    5901 -163796\n    138819 -185986\n    -69848 -96669", "output": "6"}]