#include <stdio.h>

int main() {
    int n, i;
    if (scanf("%d" , &n) != 1 || n <= 0 ||
n > 100) {
    printf("Invalid input");
    return 0;
}
int score[n];
int *ptr = score;
float sum = 0;
for (i = 0; i < n; i++) {
    if (scanf("%d", ptr + i) != 1) {
        printf("Invalid input");
        return 0;
        if (*(ptr + i) < 0 || *(ptr + i) >100) {
            printf("Invalid input");
            return 0;
        }
    sum += *(ptr + i);
  }
  float average = sum / n;
  printf("%.2f" , average);
  return 0;
}