// yukicoder: No.609 Noelちゃんと星々
// 2019.5.5 bal4u

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

#if 1
#define gc() getchar_unlocked()
#else
#define gc() getchar()
#endif
int in()   // 整数の入力（負数対応）
{
	int n = 0, c = gc();
	if (c == '-') {	c = gc();
		do n = 10*n + (c & 0xf), c = gc(); while (c >= '0');
		return -n;
	}
	do n = 10*n + (c & 0xf), c = gc(); while (c >= '0');
	return n;
}

int selection(int *a, int sz, int n) {
	int i, j, p, l, r, t;
	
	l = 0, r = sz-1;
	while (l < r) {
		p = a[(l+r)/2];
		i = l-1, j = r+1;
		while (1) {
			while (a[++i] < p);
			while (a[--j] > p);
			if (i > j) break;
			t = a[i], a[i] = a[j], a[j] = t;
		}
		if (n < i) r = j;
		if (n > j) l = i;
	}
	return a[n];
}

int y[100005];

int main()
{
	int i, N, t;
	long long ans;

	N = in();
	if (N == 1) { puts("0"); return 0; }
	for (i = 0; i < N; i++) y[i] = in();
	t = selection(y, N, N>>1);
	ans = 0; for (i = 0; i < N; i++) {
		if (y[i] < t) ans += t - y[i];
		else ans += y[i] - t;
	}
	printf("%lld\n", ans);
	return 0;
}