#include<iostream>
#include<fstream>
using namespace std;

int main()
{
	ifstream f("text.in");
	ofstream g("text.out");
	
	char text[256],*p,sep[]=", .;:!*?";
	unsigned i,rez,k=0,k2=0;


	
	f.get(text,256);
	
	for(i=0;i<strlen(text);++i)
		if(strchr("abcdefghijklmnopqrstuvwxyz",text[i])||strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZ",text[i]))
			k++;
		
	p=strtok(text,sep); 
	while(p)
	{
		k2++;
		p=strtok(NULL,sep); 

	}
	rez=k/k2;
	
	g<<rez;
	
	return 0;
}