input: Write a function to find the longest run of consecutive 1s in the binary representation of a given integer.
  assert longest_run_of_ones(156) == 3
  assert longest_run_of_ones(13) == 2
  assert longest_run_of_ones(222) == 4
output: def longest_run_of_ones(n):
      return max(map(len, bin(n)[2:].split('0')))