#include<fstream>
#include<string.h>
using namespace std;
ifstream cin("text.in");
ofstream cout("text.out");
int main()
{
	char s[1000000];
	int k=0,lung=0;
	 char *p;
	 char sep[]="',.?:;- (){}[]\"";
	 }";
	  while(!cin.eof())
	 {
	 	cin.getline(s,1000000);
	 p=strtok(s,sep);
	 while(p)
	 {
	 	k++;
	 	lung=lung+strlen(p);
	 	p=strtok(NULL,sep);
	 }
}
	 cout<<lung/k;
	 return 0;
	
}