# include <fstream>
using namespace std;
int main(void){ ifstream txt("text.in"); ofstream ma("text.out");
	char c;
	int x,l=0,cuv=0,w,d=35;
	while(!txt.eof()){
		txt.get(c);
		w=0;
		x=(int)c;
		if((x>=65 && x<=90)||(x>=97 && x<=122)){ 
			w=1; 
			l++; 
		}
		if(w &&(d<65||d>90&&d<97||d>122)) cuv++;
		d=x;
	}
	ma<<l/cuv;
	txt.close();
	ma.close();
	return 0;
}