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

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

string word;
int nr_lit=0, nr_cuv=0, total=0;
char x;

int main()
{
    while(in>>word)
    {
        for(int i=0; i<=word.length(); i++)
            if((word[i]>='a' && word[i]<='z') || (word[i]>='A' && word[i]<='Z'))
                nr_lit++;
            else
                if(nr_lit>0)
                    total+=nr_lit, nr_cuv++, nr_lit=0;
    }
    out<<total/nr_cuv;
    in.close();
    out.close();
    return 0;
}