// text.in.cpp : Defines the entry point for the console application.
//

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

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

char sir[256], tok[] = " ,.:;!?-",*q, *b;
int sum, k,i;

int litera(char s)
{
	if (('a' <= s&&s <= 'z') || ('A' <= s&&s <= 'Z'))
		return 1;
	return 0;


}

int main()
{

	fin.get(sir, 255);
	for (i = 0; sir[i];i++)
	if (litera(sir[i]))
		k++;
	q = strtok(sir,tok);
	while (q)
	{
		sum++;
		q = strtok(NULL, tok);
	}
	if (!sum)fout << 0;
	else fout << k / sum;
	return 0;
}