#include<fstream>
#include<ctype>
int main(void)
{
char c;
int k=0,nrCuv=0,p=0;
ifstream in("text.in");
while(!in.eof())
	{
	in.get(c);
	if(!in.eof()&&isalpha(c))
		{
		k++;
		p=1;
		in.get(c);
		while(!in.eof()&&isalpha(c))
			{
			k++;
			in.get(c);
			}
		}
	if(p==1)
		{
		nrCuv++;
		p=0;
		}
	}
in.close();
ofstream out("text.out");
out<<k/nrCuv<<'\n';
out.close();
return 0;
}