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

int main(void){
    char c[6];
    int N, M;
    int *p;
    
    fgets(c, sizeof(c), stdin);
    N = atoi(c);
    
    p = (int *)malloc(sizeof(int) * N);
    for(int i = 0; i < N; i++) scanf("%d", &p[i]);
    
    for(int i = 0; i < N; i++){
        for(int j = 0; j < N - i; j++){
            if(p[j] > p[j + 1]){
                M = p[j];
                p[j] = p[j + 1];
                p[j + 1] = M;
            }
        }
    }
    
    if(N % 2 == 0){
        M = p[N / 2] + p[N / 2 - 1];
        if(M % 2 == 0){
            printf("%d\n", M / 2);
        }else{
            printf("%.1f\n", (float)M / (float)2);
        }
    }else{
        printf("%d\n", p[N / 2]);
    }
    
    
    return 0;
}