#include<fstream>
using namespace std;

int main(){
	char litera;
	int lit=0,cuv=0;
	ifstream in("text.in");
	ofstream out("text.out");
	while(in.get(litera)){
		
		while(!(litera>='a'&&litera<='z'||litera>='A'&&litera<='Z'))
			in.get(litera);
		cuv++;
		while(litera>='a'&&litera<='z'||litera>='A'&&litera<='Z'){
			lit++;
			in.get(litera);
		}
	}
	out<<lit/cuv;
}