#include <fstream>
#include <iostream>
#include <string.h>
using namespace std;

ifstream fin("fact.in");
ofstream fout("fact.out");
 int main()
 {char a;
  int nr=0,litere=0,cuvinte=0;
  while(!fin.eof())
    {fin.get(a);
    if(((a>=65&&a<=90) || (a>=97&&a<=122))) nr++;
    else if(nr)
         {litere=litere+nr;
          nr=0;
          cuvinte++;
         }

    }
    fout<<litere/cuvinte;


   return 0;
 }