#include<iostream.h>
#include<fstream.h>
#include<string.h>

ifstream f("text.in");
ofstream g("text.out");

int main()
{
	int nr;
	long sm;
	nr=0;
	sm=0;
	char *sir,*cuv,*aux;
	cuv=new char[201];
	sir=new char[20001];
	f.get(sir,20000);
	f.get();
	if(!f.eof())aux=new char[20001];
	while(!f.eof())
	{
		f.get(aux,20000);
		f.get();
		strcat(sir,aux);
	}
	cuv=strtok(sir," -.,;:!1234567890()");
	while(cuv)
	{
		nr++;
		sm+=strlen(cuv);
		cuv=strtok(NULL," -.,;:!1234567890()");
	}
	g<<sm/nr;
	f.close();
	g.close();
	return 0;
}