#include <fstream>
#include <string>

using namespace std;

ifstream f ("date.in");
ofstream g ("date.out");

string str;
int suma, k, n, m;

int main()
{
    while (f >> str)
    {
        m = str.size();
        for (int i = 0; i < str.size(); i++)
        {
            n = str[i];
            if (!((n >= int('A') && n <= int('Z')) || (n >= int('a') && n <= int('z'))))
            {
                m--;
                if (i > 0 && i < str.size())
                    k++;
            }
        }
        suma += m;
        k += bool(m);
    }
    g << suma / k;
}