#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<math.h>
int main()
{
int N, cnt = 0;
double *number, sum = 0;
scanf("%d", &N);
number = (double*)malloc(sizeof(double)*N);
for (int i = 0; i < N; i++)
{
char str[100]; int flag = 0, index = 0; double num;
scanf("%s", str);
for (int i = 0; i < strlen(str); i++)
if ((str[i]<'0' || str[i]>'9') && str[i] != '.' && str[i] != '-')flag = 1;
if (flag == 1)
{
printf("ERROR: %s is not a legal number\n", str); continue;
}
for (int i = 0; i < strlen(str); i++)if (str[i] == '.')
{
index = i; break;
}
if (index != 0 && (strlen(str) - 1 - index) > 2)
{
printf("ERROR: %s is not a legal number\n", str); continue;
}
num = atof(str);
if (fabs(num) > 1000)
{
printf("ERROR: %s is not a legal number\n", str); continue;
}
number[cnt++] = num;
}
for (int i = 0; i < cnt; i++)sum += number[i];
if (cnt == 1)printf("The average of 1 number is %.2f", sum);
else if (cnt == 0)printf("The average of 0 numbers is Undefined");
else printf("The average of %d numbers is %.2f", cnt, sum / cnt);
return 0;
}