#include <iostream>
#include <fstream>
///97 122
///65 90
using namespace std;
ifstream fin("text.in");
ofstream fout("text.out");
string s;
int nr,tot,len;
int main()
{
    while (fin>>s)
    {
        len=s.size();
        for (int i=0;i<len;i++)
        {
            if ((s[i]>=97 && s[i]<=122)||(s[i]>=65 && s[i]<=90))
                nr++;
        }
        tot++;
    }
    fout<<nr/tot;
    return 0;
}