#include <iostream>
#include <fstream>
using namespace std;
string s;
int w,l,n,i,k=0;
float c;
int main()
{
    ifstream f("text.in");
    ofstream g("text.out");
    getline (f,s);
    n=s.length();
    for (i=0;i<=n-1;i++)
    {
        if (((s[i]>=65) and (s[i]<=90)) or ((s[i]>=97) and (s[i]<=122))) {l++;k=1;}
        else if ((k==1) and ((s[i]==' ') or (s[i]=='-'))) {w++;k=0;}
    }
    w++;
    c=l/w;
    g<<c;
    return 0;
}