#include <stdio.h>

int main(void){
	int cnt = 0;
	int i,j,n;
	int a[100010];
	scanf("%d", &n);
	for(i=0;i<n;i++){
		scanf("%d", &a[i]);
	}
	for(i=0;i<n;i++){
		int num = a[i];
		if(a[i] == 0){continue;}
		
		for(j=i+1;j<n;j++){
			if(num == a[j]){
				a[i] = 0;
				a[j] = 0;
			}
		}
		if(a[i] != 0){
			cnt++;
		}
	}
	
	printf("%d\n", cnt);
	return 0;
}