#include <iostream>
#include <fstream>
using namespace std;
ifstream f("text.in");
ofstream g("text.out");
int main() {


    int nrcuvinte = 0, nrlitere = 0;
    char c;
    bool cuv = false;
    double average;
    while ((f>>noskipws>>c)&&(c!='\n'))
        {
        if (((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')))
        {
            nrlitere = nrlitere + 1;
            if(cuv==false)
            {
                nrcuvinte=nrcuvinte+1;
            }
            cuv = true;
        }
        else
            if ((cuv==true) && (c==' '))
            {
                cuv=false;
            }
            else
                if(c=='-')
            {
                cuv=false;
            }
    }
    average=nrlitere/nrcuvinte;
    g<<average;

    return 0;
}