#include<fstream>
using namespace std;
ifstream fin("text.in");
ofstream fout("text.out");
int main(){
	 char x;
	 int lungime=0 , cuvinte=0 , total=0 ;
	 while(fin.get(x)){
		 if(('a'<=x&&x<='z') || ('A'<=x&&x<='Z'))
			 lungime++;
		 else{
			 if(lungime)
				 cuvinte++;
			         total+=lungime;
			         lungime=0;
		 }
	 }
	 fout<<total/cuvinte;
return 0;
}