#include <fstream>
using namespace std;
fstream in,out;
long i;
char v[1050000];
long c=0,l=0,t=0;

int main()
{
in.open("text.in",ios::in);
out.open("text.out",ios::out);
in.getline(v,1050000,'EOF');
in.close();
i=0;
while(v[i]!=0)
  {
  t=0;
  while(((v[i]>=65 && v[i]<=90) || (v[i]>=97 && v[i]<=122)) && v[i]!=0)
    {
    t++;
    i++;
    }
  if(t>0)
    {
    l=l+t;
    c++;
    }
  else i++;
  }
if(c>0)
  out<<(l/c);
else
  out<<"0";
out.close();
return 0;
}