#include #include #include #include #include #include #include #include #include #include #include typedef long long ll; typedef unsigned int uint; using namespace std; int main() { int n; cin >> n; double a[n]; for (int i = 0; i < n; i++) { cin >> a[i]; } double ans; if (n % 2 == 0) { ans = a[n / 2]; } else { ans = (a[n / 2] + a[n / 2 + 1]) / 2; } cout << ans << endl; }