#include<fstream>
#include<ctype.h>
using namespace std;

int main()
{
	ifstream f("text.in");
	ofstream g("text.out");
	
	
	int nrc=0,nrl=0;
	char c;
	
	while(!f.eof())
	{
		
		do{			
			
		f.get(c);	
			if(isalpha(c)) nrl++;
			
			
			if(f.eof()) break;
		}while(isalpha(c));
		nrc++;
		c=' ';
		while(!isalpha(c)&&!f.eof()) f.get(c);
		
		if(isalpha(c)) nrl++;
		if(f.eof()) {
			if(nrc==1) nrc--;
			break;}
		
					
	}
	if(nrc==0) g<<0;
 	else g<<nrl/nrc;
	return 0;
}