#include <iostream>
#include <fstream>
#include <string>
using namespace std;
ifstream fi("text.in");
ofstream fo("text.out");
string s;
int main()
{
    int nr=0,sum=0;
    while (fi>>s)
    {
        nr++;
        int l=0;
        for(int i=0;i<=s.size()-1;i++)
            if ((s[i]>='a'&&s[i]<='z')||(s[i]>='A'&&s[i]<='Z'))
                l++;
            else
                if (((s[i-1]>='a'&&s[i-1]<='z')||(s[i-1]>='A'&&s[i-1]<='Z'))&&i>0&&i<s.size()-1)
                    nr++;
        sum=sum+l;
    }
    fo<<sum/nr;
}