<gh_stars>0
"""
 *
 * Author:  <NAME>(coderemite)
 * Email: <EMAIL>
 *
 """
d={}
for x in map(int,[*open(0)][1].split()):
  d[x]=d.get(x,0)+1
r=0
for x in d.values():r+=x//2
print(r//2)
"""
 *
 * Author:  <NAME>(coderemite)
 * Email: <EMAIL>
 *
 """
d={}
for x in map(int,[*open(0)][1].split()):
  d[x]=d.get(x,0)+1
r=0
for x in d.values():r+=x//2
print(r//2)
*  * Author:  <NAME>(coderemite)  * Email: <EMAIL>  *