/* Implementace ukolu 2 */

#include<cstdio>
#include<algorithm>

#define MAXN 100000

using namespace std;

enum KONEC {LEVY, PRAVY};

struct endpoint
{
	int h; //vyska
	int t; //typ - LEVY nebo PRAVY
}E[MAXN]; //pole vsech koncovych bodu

int El; // pocet prvku v E

bool compare(endpoint A, endpoint B)
{
	if (A.h < B.h)
		return true;
	if (A.h == B.h && A.t > B.t) //Dulezite! Pokud ma vic intervalu stejny koncovy bod, napred se zbavime pravych - tak se vyhneme prazdnym intervalum
		return true;
	return false;
}

int N;
int list[MAXN];

int main()
{
	scanf("%d", &N);
	for (int i = 0; i < N; i++)
		scanf("%d", &list[i]);
	
	if (N == 1) {
		printf("%d\n", list[0]);
		return 0;
	}

	int a, b;
	for (int i = 1; i < N; i++) {
		a = list[i-1], b = list[i];
		if (a > b)
			swap(a, b);
		E[El++] = (endpoint) {a, LEVY};
		E[El++] = (endpoint) {b, PRAVY};
	}

	sort(E, E+El, compare);

	int bestnum = 0, bestl = -1, bestr = -1, num = 0, l;

	for (int i = 0; i < N; i++) {
		if (E[i].t == LEVY) {
			l = E[i].h;
			num++;
		}
		if (E[i].t == PRAVY) {
			if (num > bestnum) {
				bestnum = num;
				bestl = l;
				bestr = E[i].h;
			}
			num--;
		}
	}

	printf("%.1f\n", ((double) bestl + (double) bestr)/2.0);
	return 0;
}