title: determine the sum of all positive odd integers up to some number
body: <p>I tried this but it hackerearth does not accepts it. all test cases fail</p>
  
  <pre><code>def calculate(arr):
      return lambda arr: sum(xrange(1, arr + 1, 2))
  
  if __name__ == '__main__':
      arr_count = int(raw_input().strip())
  
      arr = []
  
      for _ in xrange(arr_count):
          arr_item = int(raw_input().strip())
          arr.append(arr_item)
  
      calculate(arr)
  </code></pre>
  
  <p>input:</p>
  
  <pre><code>3
  1
  2
  3
  </code></pre>
  
  <p>expected output:</p>
  
  <pre><code>1
  1
  4
  </code></pre>
  
  <p>Where am I wrong?</p>