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

#define cuvant (s>='a' && s<='z') || (s>='A' && s<='Z')

fstream f("text.in",ios::in),g("text.out",ios::out);

long nrcuv,nrlit; char s;
int ga=0,status=1,k=0;

int main()
{
//f.get(s);


while(f.get(s))
{

if(cuvant)
{ga=1;
 nrlit++;}
else if(ga)
	{nrcuv++;
	 ga=0;}
//f.get(s);
}

if(nrcuv==0)
g<<0;
else
g<<nrlit/++nrcuv;




}