#include <bits/stdc++.h>

using namespace std;

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

const int NMAX = 1e7;
char s[NMAX];

int main() {
    int sum = 0, cnt = 0;
    while(fin.getline(s, sizeof(s))) {
        int N = strlen(s);
        for(int i = 0; i < N; ++i)
            if(isalpha(s[i])) {
                int j = i;
                while(isalpha(s[j]) && j < N)
                    ++j;
                sum += j - i;
                ++cnt;
                i = j;
            }
    }
    if(cnt == 0)
        fout << 0;
    else
        fout << sum / cnt;
}