#include <fstream>
#include <string>
#define MAX 1000000

using namespace std;

char t[MAX];
    
int main() {
    ifstream f("text.in");
    ofstream g("text.out");
    int len, i, nrWord = 0, nrLetter = 0;
    
    /*while (!f.eof()) {
		f.getline(t,MAX);
		len = strlen(t);
		i = 0;
		while ( i < len ) {
			if ( isalpha(t[i]) ) { 
				nrLetter++; 
				if ( i == len - 1 ) 
					nrWord++; 
			}
			else 
				if ((i != 0) && (isalpha(t[i-1]))) nrWord++;
			i++;
		}
	}*/

    while (!f.eof()) {
        f.getline(t,MAX);
        len = strlen(t);
		i = 0;
        while ( i < len ) {
            while ( (i < len) && (isalpha(t[i])) ) { 
                i++;
                nrLetter++;
            }
            if ( i > 0 ) nrWord++;
            while ( (i < len) && !(isalpha(t[i])) ) { 
                i++;
            }
        }
    }
    
    if ( !nrWord ) 
        g << 0;
    else {
        g << nrLetter / nrWord;    
    }
    
    return 0;
}