#include <iostream>
#include <fstream>
using namespace std;
ifstream fi("text.in");
ofstream fo("text.out");
string s;
unsigned int sum,k,i;

int main()
{
    sum=0;k=0;
    while(!fi.eof())
    {
         ret:
         if(fi.eof()) goto en;
         fi>>s;
         if(s.length()<2) goto ret;
         
         for(i=0;i<s.length();i++)
         {
         if((i==s.length()-1)){if((s[i]==',') || (s[i]=='!') || (s[i]=='.') || (s[i]==':')) {}}
         else 
         {
              if(s[i]=='-'){sum+=i; k++; s.erase(0,i+1); goto ret;}
              if((!((int)s[i]>=96) && ((int)s[i]<=122)) && (!((int)s[i]>=65) && ((int)s[i]<=90))) goto ret;}
         }
         
         sum+=s.length();
         k++;
    }
    en:
    if(k!=0)fo<<sum/k;
    fi.close();
    fo.close();
}