#include <iostream>
#include <fstream>

using namespace std;

int noword,noletters;
string s;

bool isLit(int i){
    if ( (s[i]>='a' and s[i]<='z') or (s[i]>='A' and s[i]<='Z') ) return 1;
    return 0;
}

int main(){
    ifstream f("text.in");
    ofstream g("text.out");
    for(; !f.eof(); ){
        getline(f, s);
        s+=' ';
        for (int i=0;i<s.size();++i){
            if ( isLit(i) == 0 && (i > 0) && isLit(i-1) == 1) ++noword;
            if ( isLit(i) ) noletters++;
        }
    }
    g << noletters / noword;

    f.close();
    g.close();
    return 0;
}