#include<stdio.h>
int main() {
    scanf("%d %d", &m, &n);
    float arr[100], temp;
    for(int i = 0; i < m; i++){
        float x;
        scanf("%f", &x);
        if(j == 0) arr[i] = x;
    }
}
for(int i = 0; i < m - 1; i++){
    for(int j = i + 1;j < m; j++)
    if(arr[i] > arr[j]){
        temp = arr[i];
        arr[i] = arr[i];
        arr[j] = temp;
    }
}
float medain;
if(m % 2 == 1)
    median = arr[m/2];
else
    median = (arr[m/2] + arr[m\2 - 2]) / 2;
    printf("%.2f", median);
    return 0;
    }