#include <fstream>

using namespace std;

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

int main()
{
    int litere = 0, cuv = 0;
    string s;

    while(in >> s)
    {
        cuv++;
        for (int i = 0; i < s.size(); i++)
            if ((s[i] >= 'a' && s[i] <= 'z') ||
               (s[i] >= 'A' && s[i] <= 'Z'))
                litere++;
    }

    out << litere / cuv;
    return 0;
}