// yukicoder: No.182 新規性の虜
// 2019.4.13 bal4u

#include <stdio.h>
#include <stdlib.h>

//// 高速入力
#if 0
#define gc() getchar_unlocked()
#else
#define gc() getchar()
#endif
int in()    // 非負整数の入力
{
	int n = 0, c = gc();
	do n = 10 * n + (c & 0xf), c = gc(); while (c >= '0');
	return n;
}

int a[100005]; int N;

int cmp(const void *a, const void *b) { return *(int *)a - *(int *)b; }

int main()
{
	int i, ans;

	N = in();
	for (i = 1; i <= N; i++) a[i] = in();
	qsort(a+1, N, sizeof(int), cmp);
	ans = 0;
	for (i = 1; i <= N; i++) {
		if (a[i] != a[i - 1] && a[i] != a[i + 1]) ans++;
	}
	printf("%d\n", ans);
	return 0;
}