#include<fstream.h>
#include<string.h>
# define Nmax 32767
char linie[Nmax];

int estecaracter(int p)
{
	if( (linie[p]>='a') &&(linie[p]<='z')) return 1;
	if( (linie[p]>='A') &&(linie[p]<='Z')) return 1;
	return 0;

}
int main(void)
{
	unsigned long litere=0,n,i,loc,p,j;
	ifstream in("text.in");
	p=0;
	while(!in.eof())
	{	in.getline(linie,Nmax,'\n');
		n=strlen(linie);
		i=0;
		while(i<n)
		{	while((estecaracter(i)==0)&&(linie[i]!=NULL))
				i=i+1;
			loc=0;
			while((estecaracter(i)==1)&&(linie[i]!=NULL))
			{
				loc++;
				litere++;
				i++;
			}
			if(loc>0)
			{
				p=p+1;
			}
		}
	}
	in.close();
	ofstream out("text.out");
	out<<(int)litere/p;
	out.close();
	return 0;
}