#include <fstream>
using namespace std;
ifstream f("text.in");
ofstream g("text.out");
int n,nrc,nr,nrcuv;
char c;
int main()
{   while(!f.eof())
    {   f.get(c);
        if((c>=65 and c<=90) or (c>=97 and c<=122))
        {   nr=0;
            while((c>=65 and c<=90) or (c>=97 and c<=122))
            {   f.get(c);
                nr++;
            }
            nrc+=nr;nrcuv++;
        }
    }
    g<<nrc/nrcuv;
    return 0;
}