#include <cstdio>
#include <algorithm>
int main(){
    int N;
    scanf("%d", &N);

    int A[100000];
    for(int i=0;i<N;i++){
        scanf("%d", A+i);
    }

    std::sort(A, A+N);

    int count = 0;
    for(int i=0,j=0;i<N;){
        while(j < N && A[j] == A[i]){j++;}

        if(j-i == 1){count++;}
        i = j;
    }

    printf("%d\n", count);
}