#include <iostream>
#include <fstream>
#define ull unsigned long long
#define DIM 100005
using namespace std;

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

char buff[DIM];
int poz = 0;
ull ln_total, nr_cuv;

int main()
{
    f.getline(buff, DIM);
    while (!f.eof()) {
        while (!((buff[poz] >= 'a' && buff[poz] <= 'z') || (buff[poz] >= 'A' && buff[poz] <= 'Z'))) {
            if (++poz == DIM)
                f.getline(buff, DIM), poz = 0;
        }
        bool ok = false;
        while ((buff[poz] >= 'a' && buff[poz] <= 'z') || (buff[poz] >= 'A' && buff[poz] <= 'Z')) {
            ok = true;
            ++ln_total;
            if (++poz == DIM)
                f.getline(buff, DIM), poz = 0;
        }
        if (ok)
            ++nr_cuv;
    }
    g << ln_total / nr_cuv;
    return 0;
}