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


int cmpn(const void *a, const void *b);


int main(void){
    unsigned short N, i;
    short a[1000];
    
    scanf("%hu\n", &N);
    for(i=0; i<N-1; i++) scanf("%hd ", &a[i]);
    scanf("%hd\n", &a[i]);
    qsort(a, N, sizeof(short), cmpn);
    if(N%2) printf("%hd\n", a[N/2]);
    else printf("%f\n", (a[(int)(N/2-0.5)] + a[(int)(N/2+0.5)]) / 2.0);
    
    return 0;
}


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