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

ifstream is("text.in");
ofstream os("text.out");

int suma_litere;
string str;

int main()
{
    int i = 0;
    while(is >> str)
    {
        for(int j = 0; j < str.length(); ++j)
        {
            if(isalpha(str[j]))
                suma_litere++;
        }
        i++;
    }
    os << suma_litere / i;

    is.close();
    os.close();
    return 0;
}