#include <iostream>
#include <fstream>
#include <string.h>


using namespace std;

ifstream intrare("text.in");
ofstream iesire("text.out");


int main()
{
    char sir;
    long long int s=0,nr=0;

    while(intrare>> noskipws >>sir){


        if(isalpha(sir)){
            nr++;

        while(isalpha(sir)){
            s++;
            intrare>> noskipws >> sir;

        }

        }


    }
    iesire<<s/nr;




    return 0;
}