#include<fstream.h>
#include<string.h>
int main(){
char a[65535];
unsigned int s=0,k=0,i,y=0;
ifstream f("text.in");
ofstream g("text.out");
while(!f.eof())
    {
     f>>a;
     for(i=0;i<strlen(a);i++)
	{
	if((a[i]>=65&&a[i]<=90)||(a[i]>96&&a[i]<123))
		{ while((a[i]>64&&a[i]<91)||(a[i]>=97&&a[i]<=122))
		       {k++;i++;}
		  y++;s+=k;
		}
	k=0;
	}
    }
g<<(int)s/y;
return 0;
}