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

int main()
{
    ifstream f("text.in");
    ofstream g("text.out");

    std::string cuv;
    int s=0, v=0;
    while (f>>cuv)
    {
        if (cuv.size()>1||(('a' <= cuv.at(0)) && (cuv.at(0) <= 'z')) || (('A' <= cuv.at(0)) && (cuv.at(0) <= 'Z')))
        {
            v++;
            for (size_t i=0; i<cuv.size(); i++)
            {
                if ((('a' <= cuv.at(i)) && (cuv.at(i) <= 'z')) || (('A' <= cuv.at(i)) && (cuv.at(i) <= 'Z')))
                {
                    s++;
                }
                else if (cuv.size()>i+1)
                {
                    if (cuv.at(i+1)>=65||cuv.at(i+1)<=122)
                    {
                        i++;
                        s++;
                        v++;
                    }
                }
            }
        }

    }

    g << int(s/v);
}