#include<fstream.h>
#include<string.h>


ifstream in("text.in");
ofstream out("text.out");

int main(){
	char s[1000101];
	int ln,m=0,cuv=0,i,p;
	while(in.get(s,1000101)&&
	in.get()){
	ln=strlen(s);
	for(i=0;i<ln;i++)
		if((s[i]>='A'&&s[i]<='Z')||(s[i]>='a'&&s[i]<='z')){m++;
	p=1;
		}
		else if(p){cuv++;
		p=0;
		}
	
	if(p==1)cuv++;
	p==0;
	}
	if(m==0||cuv==0)
		out<<0;
	else out<<m/cuv;
	
}