#include <fstream.h>

int main()

{char l1,l2;
 long cuvant=0, litera=0;

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

 fin.get(l1);
 fin.get(l2);

 while (!fin.eof())
	{
	 if ((l1>=65 && l1<=90) || (l1>=97 && l1<=122))
		{
		 litera++;
		 if (l2<65 || (l2>90 && l2<97) || l2>122)
			cuvant++;
		}

	 l1=l2;
	 fin.get(l2);
	}

 fout<<litera/cuvant;

 fin.close();
 fout.close();

 return 0;
}