#include<fstream>

using namespace std;
int main()
{
ifstream fin("text.in");
ofstream fout("text.out");
int litera=0, cuvant=0, t=0, medie;
char s;
while(fin.get(s))
{
if(('a'<=s && s<='z')||('A'<=s && s<='Z'))
litera++;
else
{
if(litera)
cuvant++;
t=t+litera;
litera=0;
}
}
medie=t/cuvant;
fout<<medie;
fin.close();
fout.close();
return 0;
}