#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(){
    int n;
    if(scanf("%d", &n) != 1) return 0;
    int c;
    while((c = getchar()) != '\n' && c !=EOF);
    int total_usia = 0;
    char buffer[50];
    for(int i = 0; i < n; i++){
        if(fgets(buffer, sizeof(buffer), stdin) != NULL){
            buffer[strcspn(buffer, "\r\n")] = 0;
            char age_str[3];
            age_str[0] = buffer[0];
            age_str[1] = buffer[1];
            age_str[2] = buffer[2];
            int usia = atoi(age_str);
            total_usia += usia;
            char *nama = buffer + 2;
            printf("%s\n", nama);
        }
    }
    if (n > 0){
        double rata_rata = (double)total_usia / n;
        printf("%.2f\n", rata_rata);
    }
    return 0;
}