#include<fstream>
#include<cctype>
using namespace std;
ifstream fin("text.in");
ofstream fout("text.out");
string cuv;
int main()
{
	bool ok;
	int n, nrcuv = 0, i, s = 0;
	while ( fin >> cuv )
	{
		n = cuv.size();
		ok = 0;
		for ( i = 0; i < n; i++ )
		{
			if ( !isalpha(cuv[i]) )
			{
				n--;
				if ( cuv[i] == '-' && isalpha(cuv[i+1]) && isalpha(cuv[i-1]) )
					nrcuv++;
			}
			if ( isalpha(cuv[i]) )
				ok = 1;
		}
		s += n;
		if ( ok )
			nrcuv++;
	}
	fout << s/nrcuv;
	fin.close();
	fout.close();
	return 0;
}