#include<stdio.h>
int main(){
    int n, firstDigit, lastDigit;
    float median;
    scanf("%d", &n);
    if(n<0){
        printf("Invalid input");
        return 0;
    }
    lastDigit = n % 10;
    while(n >= 10){
        n = n / 10;
    }
    firstDigit = n;
    median (firstDigit + lastDigit) / 2.0;
    printf("% .1f, median");
    return 0;
}