#include <bits/stdc++.h>

using namespace std;
ifstream in("text.in");
ofstream out("text.out");
string sir;
int i;
int numarare()
{
    int k=0;
    for(i=0; i<sir.size(); i++)
        if(isalpha(sir[i]))
            k++;
    return k;
}
int main()
{
    int k=0, c=0;
    while(in>>sir)
    {
        c=c+numarare();
        k++;
    }
    out<<c/k;
    return 0;
}