#include <bits/stdc++.h>

using namespace std;
ifstream fin("text.in");
ofstream fout("text.out");
long long n,k,kk,i;
string s;
int main()
{
    while(fin >> s)
    {        k++;
        for(i = 0; i <= s.size(); i++)
            if(('a' <= s[i] && s[i] <= 'z') || ('A' <= s[i] && s[i] <= 'Z'))
                kk++;
    }
    fout << kk/k;
    return 0;
}