#include <stdio.h>

int main()
{
    int n;
    int alley[1000];
    int i,j,k;
    int temp;
    double ans;
    
    scanf("%d",&n);
    for(i=0;i<n;i++){
        scanf("%d",&alley[i]);
    }
    
    for(j=0;j<n-1;j++){
        for(k=0;k<n-j-1;k++){
            if(alley[k]>alley[k+1]){
                alley[k]=temp;
                alley[k]=alley[k+1];
                alley[k+1]=temp;
            }
        }
    }
    if(n%2==0){
        ans=((alley[n/2-1]+alley[n/2])/2.0);
    }
    else{
        ans=(double)alley[n/2];
    }
    printf("%.1f",ans);
    return 0;
}