#include <bits/stdc++.h>

using namespace std;

string sir;
ifstream in("text.in");
ofstream out("text.out");

int main()
{
    int nr=0, lit=0, cuv=0;

    while(in>>sir)
    {
        for(auto a:sir)
            if(isalpha(a))
                cuv++;
            else if(cuv)
                nr++, lit+=cuv, cuv=0;

        if(cuv)
            nr++, lit+=cuv, cuv=0;
    }

    out<<lit/nr;
    return 0;
}