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