#include<fstream>
using namespace std;
//ifstream in("text.in");
ofstream out("text.out");
int main()
{
	FILE *file=fopen("text.in","r");
	char t,x;
	fscanf(file,"%c",&t);
	int cuvant=0,litere=0;
	if((t>='a' && t<='z')||(t>='A' && t<='Z'))
	++cuvant;
	while(fscanf(file,"%c",&x)>-1)
	{
		
			if	((x>='a' && x<='z')||(x>='A' && x<='Z'))
			{
				++litere;
			if(!(t>='a' && t<='z')&&!(t>='A' && t<='Z'))
				++cuvant;
		
			}
		t=x;
	}
	out<<litere/cuvant;
	return 0;
}