#include<fstream>
#include<string>
using namespace std;

int main()
{
    string cuv;
    int i,c=0;
    unsigned int car=0;
    ifstream fin("text.in");
    ofstream fout("text.out");

    while(!fin.eof())
    {
         fin>>cuv;
         i=0;
        for(i=0;i<cuv.length();i++)
         if((cuv[i]<='z'&&cuv[i]>='a')||(cuv[i]<='Z'&&cuv[i]>='A'))
          car++;
        c++;
    }
    fin.close();
    fout<<car/c;
    fout.close();
}