#include <iostream.h>
#include <string.h>
#include <fstream.h>
fstream f("text.in",ios::in);
fstream g("text.out",ios::out);
char a;
int s,k,i,ok,l,n,nrlitere,nrcuv;

int main ()
{
  ok=0;
  while (f>>a)
	{
	  s=l;
	  i=k+1;
	  if (a>='A'&&a<='Z' || a>='a'&&a<='z') {
						  ok=1;
						  l++;
						 }
		else if (ok) {
			       k++;
			       n++;
			      }
	 }
  if (a>='A'&&a<='Z' || a>='a'&&a<='z') n++;
  nrcuv+=n;
  nrlitere+=s;
  g<<nrlitere/nrcuv;
  f.close();
  g.close();
  return 0;
}