#include<fstream.h>
fstream in,out;
long i;
char v[10500];//00
long c=0,l=0,t=0;
int main()
{in.open("text.in",ios::in);
out.open("text.out",ios::out);
in.getline(v,1050000,EOF);
i=0;
while(v[i]!=0)
	{t=0;
	while(((v[i]>=65&&v[i]<=90)||(v[i]>=97&&v[i]<=122))&&v[i]!=0)
		{t++;
		i++;}
	if(t>0)
		{l=l+t;
		c++;}
	else
		i++;}
if(c>0)
	out<<(l/c);
else
	out<<"0";
return 0;}