n = 7

arr = [ 1,2,1,2,1,3,2 ]

def matchingPairs(qty,socks):
  pairs = 0
  counts = {}
  for s in socks:
    if s in counts:
      counts[s] += 1
    else:
      counts[s] = 1

  print(counts)

  total  = 0
  for val in counts.values():
    total = total + int(val/2)
  return total


print (matchingPairs(n,arr))