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