#include <bits/stdc++.h>

using namespace std;

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

char caracter;
bool in_platou = false;
int lungime, suma, nr;

int main()
{
	while(!fin.eof())
	{
		caracter = fin.get();
		if(((int)caracter > 64 and (int)caracter < 91) or ((int)caracter > 96 and (int)caracter < 123))
		{
			if(in_platou)
			{
				++lungime;
			}
			else
			{
				++nr;
				in_platou = true;
				lungime = 1;
			}
		}
		else
		{
			if(in_platou)
			{
				in_platou = false;
				suma += lungime;
			}
		}
	}
	fout << suma / nr << '\n';
	return 0;
}