#include <iostream>
#include <fstream>
#include <cstring>

std::ifstream f("text.in");
std::ofstream g("text.out");


int main()
{
    char c1, c2;

    int nrCuv = 0;
    int nrLit = 0;

    std::string cuv;
    int index;

    while(f >> cuv) {
        nrCuv ++;
        index = 0, c1 = cuv[0];
        if(isalpha (c1)) nrLit ++;
        c2 = cuv[++ index];

        while(index != cuv. size()) {
        if(isalpha (c2)) {
            nrLit ++;
            if(!isalpha (c1))
            nrCuv++;
        }

        c1 = c2;
        c2 = cuv[++ index];
        }
    }

    //std::cout << nrLit << ' ' << nrCuv;
    g << nrLit / nrCuv;


    f.close();
    g.close();

    return 0;
}