#include<bits/stdc++.h>

using namespace std;

int words, letters;

string word;

int main()
{
    freopen("text.in", "r", stdin);
    freopen("text.out", "w", stdout);

    while(cin >> word)
    {
        words++;

        for(char i : word)
        {
            if(isalpha(i)) letters++;
        }
    }

    cout << letters / words;

    return 0;
}