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

int main()
{
  int sum = 0, average;
  char str[256];
  scanf("%s", str);

  for(int i = 0; i < strlen(str); i++)
  {
    sum += str[i];
  }

  average = sum / strlen(str);

  printf("average : %d : %c\n", average, average);

  return 0;
}