#include <fstream>
#include <iostream>
using namespace std;
ifstream in( "text.in");
ofstream out("text.out");

int main()
{
	char sir[1000001],c,*p,*q;
	int i=0,litere=0,cuvinte=0,medie=0,len;
	while(in>>noskipws>>c)
		sir[i++]=c;
	len=i-1;
	sir[i]='\0';
	p=sir;
	while(!isalpha(*p))
		p++;
	q=p;
	while(p<sir+len && q<sir+len)
	{
		while(isalpha(*q) && q<sir+len)
			q++;
		litere= litere + (q-p);
		cuvinte++;
		p=q;
		while(!isalpha(*p) && p<sir+len)
			p++;
		q=p;
	}
	out<<litere/cuvinte;

    
    return 0;
}