#182 new
# your code goes here
N=int(input())
A=[int(i) for i in input (). split ()]
B=[1]*N
i=0
C=0
while i<len(A):
    j=i+1
    nd=0
    while j<len(A):
        if A[i]==A[j]:
 #           print (i)
      #      A.pop(j)
            B[i]=0
            B[j]=0
   #         nd=1
        j+=1
   # if nd==0:
   #     C+=1
    i+=1
S=0
for i in range (N):
    S+=B[i]
print (S)