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

ifstream fin("fact.in");
ofstream fout("fact.out");
 int main()
 {char a[1000];
  int nr=0,litere=0,k;
  while(!fin.eof())
    {fin>>a;
    nr++;
    k=strlen(a);
    for(unsigned int i=1;i<=strlen(a);i++)
        {if(((int(a)<=90&&int(a)>=65)||(int(a)<=122&&int(a)>=97))) k--;

        }
    litere=litere+k;
    }
    fout<<litere/nr;


   return 0;
 }