#include<fstream>
using namespace std;

int main()
{
    char cuv[50];
    int i,c=0;
    unsigned int car=0;
    ifstream fin("text.in");
    ofstream fout("text.out");

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