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

int main()
{
	ifstream f("text.in");
	ofstream g("text.out");

	int nrc=0,nrl=0;
	while(!f.eof())
	{
		char c;
		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(f.eof()) break;
		if(isalpha(c)) nrl++;
		
	}
	//nrl++;
	g<<nrl/nrc;

	return 0;
}